350 Tbi Misfire

Introduction. So i have a chevy 350 i rebuilt recently and have put about 50 miles on it and it ran great. 1991 chevy 1500 350 tbi manual transmission schematic [DATE] [DATE] [NICK] [COMMENTSCOUNT] Comments on 1991 chevy 1500 350 tbi manual transmission schematic RockAuto ships auto parts and body parts from over manufacturers to customers' doors worldwide, all at warehouse prices. I feel better talking to my regular mechanic now that I know what the problem is and how much I can expect it to cost. 350 TBI w/T5 - Check engine light? Backfire/misfire issue with supercharged TBI. They are not like the "swirl port heads" either. Re: Lashing the valves on '99 350 vortec Turn the valve rocker arm nuts clockwise until all of the valve lash is removed. The local shop said they replaced it, but it doesn't look new. Tbi for chevy 350 Tbi for chevy 350. Getting closer to home, it began backfiring through the exhaust. I forgot to mention that it will skip and misfire even after the engine comes up to temperature. I have A 1991 GMC SIERRA, 350,no fuel no spark, have fuel to the tbi, changed coil, ignition module, tested pick up coil good, check engine light comes on with key, fuses good, have power at coil (pink wire), I'm running out of ideas. I've read that an ECU used on 1988-92 TBI equipped V8s (#1227746) can be used in place of the earlier, original ECUs (the 1982 ECU uses service number 1225550). 93Lee · Registered. The truck has 190K miles on it and runs fine other than a misfire. The HEI design incorporates the vacuum advance mechanism, the ignition coil and a permanent magnet assembly that has a pole lined with teeth and a pick-up coil. Last year at the end of the season the boat started running bad after running it for about 30 min. A faulty ignition module can affect ignition timing, resulting in an engine that misfires and runs rough. The computer uses this information to determine how much fuel is needed to maintain the correct air/fuel mixture and when extra fuel is needed if the throttle suddenly opens wide. How to adjust idle on 350 tbi How to adjust idle on 350 tbi. Volvo Penta Mercruiser 454 V8 7. l … read more. Changed it out and the thing ran great again. It would cause a check engine light yes, but not affect the way the engine runs. 7L 350 Long Block Crate Engine is on sale now. The truck has 190K miles on it and runs fine other than a misfire. i have a 1995 chevy 2500 350 tbi a/t. P1391 Wheel Speed Sensor 1, G-Sensor Circuit Performance. 7 v8 runs perfect. It is also way down on power and stumbles until you really give it some gas, but even then, you can tell its low on power. My parents had a 1997 Yukon that did similar things. The engine is perfect but when i try to accelerate onto plane. It will cause the idle speed to randomly fluctuate to different speeds rather than stay at one constant speed. Lots of folks lately with Holley issues. It will loose power when at speed and when accelerating. So on average, the total cost of the replacement, along with the labor cost, is $135 to $460. We expect this ignition wiring diagram chevy 350 tbi engine photo will present you with. Too much air flowing into the intake causes the engine to lean out [too much air in relation to the fuel] and misfire. TCS EQ Ratio Minimum: Minimum EQ Ratio when TCS is active. You can hire a mechanic or take your vehicle to a garage to have the knock sensor replaced after diagnosis. Your fuel injector is the main gas delivery system utilized in automotive engines, but if it's defective or clogged, your ride can have problems starting. 87 2wd half ton completely stock 305 TBI How can I tell if the system is going from open loop (when cold) to closed loop (after it heats up) did a smog check and came back with high hydro carbon and high co as you would expect to see when cold. It's packed with all the features you need to get a reliable 330 horsepower and 380 ft/lbs of torque from a time-tested combination of new GM Performance Parts. Does this misfire occur on flat terrain with low engine load and part throttle? Or is it when hill climbing, or coasting, these things will help myself and others diagnose your problem There are lots of folks here smarter at this than me. The EGR valve was faulty so I replaced it. It's fairly significant while cruising at highway speeds 60mph(1600/1700rpms) and under a load it isn't as noticeable. If the fuel mixture becomes too lean, "lean misfire" may occur as the load on the engine increases. The first sign of a car overheating is either when the needle on the temperature gauge pushes its way into the ominous red zone or the “Check Engine” or “Temperature” malfunction indicator light on the dashboard casts a sinister glow. First I start with a new Fuel pump, STOCK 75lph TBI fuel pump will only support about 230hp before the fuel pressure drops like a rock. One contact is for the coil wire, and the remaining eight are for the 350's eight cylinders. If the engine is or has been misfiring, do not install the new ignition module until after the source of the misfire has been corrected. Thanks for the reply. Carbureted or TBI 5. There should be a decent amount of fuel streaming out, if not, you have a pressure problem. Belltech!. Is this a completely stock '79 350?. I think it was a 2 valve pushrod, but I could be wrong. Misfire perhaps. Left alone, the liquid in the radiator eventually boils over, and steam rolls out from […]. How to adjust idle on 350 tbi How to adjust idle on 350 tbi. 96 Chevy C1500 4. As long as I stayed under about 1/4 throttle, it was okay. A failed injector can cause a regular misfire, rough idle, poor fuel economy, roughness or loss of power (and will register a trouble code that will illuminate the Check Engine light). I need some help diagnosing my boats problem. Chevy 383 / 350 HP 4 Bolt Performance TBI Balanced Crate Engine Truck Camaro $ 3,395. 8 TBI that I'm swapping a 2000 Vortec 350 CSFI into. It has saved me hours and hours of trying to figure out where a misfire is coming from. What the Home Mechanic Needs to Know about O2 Sensors Download PDF. P1391 Wheel Speed Sensor 1, G-Sensor Circuit Performance. We're not talking about a knocking engine or one that idles rough or stalls. Sounds like a machine gun. That fixed the rough idle and it drove fine for a day or two. NOTE: This tutorial covers the EGR valve of the 1987-1995 throttle body fuel injection (TBI) system of the 4. 3/4 ton, 350 TBI engine with 125,000 miles. 6 litre cars. 73 350 - 700R4 - 4. I bought the truck two weeks ago, drove it home from a neighboring city, two highway hours away, no problems. I have replaced the. The GM TBI (Throttle Body Injection) system uses a pair of low pressure fuel injectors mounted above the throttle body opening. 7l tbi l05 vin=k 94 c,k,p 5. I have A 1991 GMC SIERRA, 350,no fuel no spark, have fuel to the tbi, changed coil, ignition module, tested pick up coil good, check engine light comes on with key, fuses good, have power at coil (pink wire), I'm running out of ideas. The problem was the fuel filter. 00; Ford 351 Windsor 345 HP Turn Key High Performance Balanced Crate Engine $ 4,495. 0l tbi l03 vin=h 92 c,k,g 5. 7L Hesitation, Cuts out, Misfire Posted to GM Driveability on 3/7/2009 23 Replies Thanks for taking the time to read this,your input is appreciated. Once the problem has been diagnosed, you will be provided with an upfront quote for the recommended fix and receive $20. You may have a misfire, a vacuum leak, or a clogged/faulty idle air control valve. South Main Auto Repair LLC. 7 tbi misfire,buck,stalls, 2 Answers. There are examples in the 500 hp range on stock block internals. 1995 k1500 5. It idles terribly. The tachometer is just showing what the engine is already doing; it does not affect how the engine runs. P1381 Misfire Detected - No Communication with Brake Control Module. The most popular service booked by readers of this article is Vehicle Engine Mechanical Inspection. 5-liter diesel may clog the fuel filter. Silverado & Fullsize Pick-ups - 1998 z71 350 vortec missfire - I have 1998 z71 started missing sounds like I have put I preformance cam and hard to start. I'm having problems with my engine which is a gen 5 454 tbi 220 model made in 1992. 03 cavalier 2. hello, I've got an 89 350 tbi chevy that has a misfire. 7 tbi when at idle it has a low to the idle. How To Test The GM Ignition Control Module (1995-2005). They have an aluminum piston that has the stepped metering rods hanging on it and a spring under the piston that performs the "power valve" job. If you’ve replaced your Ford electronic throttle body or you’ve disconnected the battery, you must do a Ford throttle body relearn to establish a new baseline idle. A cast-iron block with four-bolt main caps is the foundation for the 350 HO, which is topped with iron Vortec heads fitted with 1. Chevy V8 Misfire Caused by Excessive Cam Retard. 060 flat top pistons, Sportsman II 64cc heads 2. When shifting into drive, engine runs at idle rpm, when throttle is pushed down to come off idle, engine coughs & dies. , if you want to fix it as cheap as possible. There is a knock in the engine. It does it sometimes at idle when cold and does it just going down the road at 40-45mph when it gets into overdrive and is running in the 1500RPM range. 3L V-6 engine. Checking trouble codes is only one thing to check. I hear a very faint knock/ping at idle, but its so light I cant tell if its internal components or a timing issue, I sometimes hear a slight stumble coming from the exhaust during idle, sorta like a misfire. 7 liters, of displacement. I'm working my way through a 350 TBI/TH700R4 swap. Timing set at 0 BTDC with advance disconnected at ECM. For 1982 and 1984, the 5. My customers have been complaining about this for years, but every time they show up with the vehicle everything worked properly. I have the main coil unit, a slave solenoid for the starter, and a 50 amp breaker that is wired to the slave solenoid and the starter. 7 rough idle problem Hello, I have a 95 GMC Sierra 1500 4x4 with the 5. Does this misfire occur on flat terrain with low engine load and part throttle? Or is it when hill climbing, or coasting, these things will help myself and others diagnose your problem There are lots of folks here smarter at this than me. Torque-to-Angle Indicator (Part Number TRQ-1) With T-T-Y head bolts, the Torque-To-Angle Indicator (Part Number TRQ-1) should be used in conjunction with. Unfortunately, most vacuum gauge manufacturers don't provide easy-to-follow instructions and diagrams to help users interpret gauge readings, rendering the gauges themselves virtually useless. 350 tbi 350 tbi. when im cruising i can feel it lurching a little forward like a misfire feels like. One contact is for the coil wire, and the remaining eight are for the 350's eight cylinders. I have seen a couple of videos on you tube of the same issue but they don't seem to have found the cure. 1991 K5 TBI 350 with SM465. If you're questioning what is normal engine noise, I may have the answer. As a result, Each time the piston changes direction, there is a noise from the metal hitting metal. 7 350, has 176,000 - GMC 1995 Sierra question. If there are no misfire codes, a common cause of acceleration stumble is a bad throttle position sensor (TPS). I have a 1994 Buick Century and in the last month or so the engine started making a noise that sounds as if it were literally was a diesel engine. Acrobat Printable Version. 1989 Chevrolet C1500 Cheyenne 5. 2009 - GMC - Acadia 2009 - GMC - Acadia SLE-1 AWD 2009 - GMC - Acadia SLT-1 AWD 2009 - GMC - Acadia SLT-2 AWD 2009 - GMC - Canyon Extended Cab 2009 - GMC - Envoy 2009 - GMC - Envoy Denali 4WD 2009 - GMC - Envoy SLE-2 4WD 2009 - GMC - Savana Cargo Van G 1500 2009 - GMC - Savanna 2009 - GMC - Sierra 3500HD Crew Cab SLT 2009 - GMC - Sierra Hybrid 2009 - GMC - Yukon 4WD SLE-1 2009 - GMC - Yukon. The carb I am using is a NOS Holley 9834-1 Here is what happens: Car starts fine hot or cold. Bad coil pack or plugs. The O2 sensor reads oxygen and since engine misfire leaves a lot of oxygen (read: unburned mixture) present, the exhaust leaves the combustion chamber and this. Re: What would cause a fuel gauge to peg way past full? did you tear into it to make sure it just wasnt loose or disconnected write on the sender itself or maybe the float is stuck past full not even touching the contacts, If i read right you didnt have to open it up at all, it came fully assembled, and the grey is most definatley pump and purple is gauge, i would definatley check ground. Email * Message. It seems to starve at higher rpms, and when it does idle the rpm's swing from hig Sounds like the fuel pump is going bad(or in this case,has gone bad). First of all I would like to say hello to everyone I am new to the site. carb cleaner and the like will not work on a fuel injected engine like it does on a carbrurated engine. 7L 350 Long Block Crate Engine is on sale now. Chevy V8 Misfire Caused by Excessive Cam Retard. Running very rich, down on power. Volvo Penta Mercruiser 454 V8 7. I feel better talking to my regular mechanic now that I know what the problem is and how much I can expect it to cost. The O2 Sensor is An Important Part of your Emissions System. Seems to run good under steady state operation with a light load, as soon as you hit the gas quickly, it hesitates and sounds bad. This video demonstrates this process. I'm working my way through a 350 TBI/TH700R4 swap. the tach read 0 yes zero and below, llights are dim and driving my tach reads normal untill i slow down the the problem reoccurs. Minor but has only just started after 3 weeks. check for vacuum leaks by spraying carb cleaner on all the vac lines and tbi base. 7L, about 235,000 miles on original motor. I have a knock count even at idle with the timing at 0 degrees. So I figured I had a broken crankshaft and disassembled the. I've been battling a very intermittent "misfire" all season in my Holley HP EFI RAMJET 350 setup. ECT: This table is used to determine the minimum Equivalence Ratio when in open loop mode. On a stock motor with a mild tune you’re looking at 250 hp & 320-350 tq. This motor stood the test of time for three decades and and be found in every General Motors division except for Saturn. org : F-Body : Chevrolet Camaro, IROC, Z28, Pontiac Firebird, Trans Am and on the Fullsize Chevy Engine Performance forum at FULLSIZEforums - Chevy Truck so it's not just hearsay. I had the timing light on it and noticed the flash became intermittent on multiple cylinders. If it backfires when you let off the gas peddle it has air getting into the exhaust, either an exhaust gasket or cracked manifold before the catalytic converter or the emission control's Air Injection system. Email * Message. I have a 97 silverado 3500 with the vortec 454 in it. Omaha, NE 68134 (402) 393-7888 Mon-Fri: 7:30am-5:30pm. It does it a lot when I get up to 40 mph. A multiple misfire can certainly cause the engine to surge. P0118 CTS, P0507 ERGvalve, P0301 misfire #1. My son's has a. A failed injector can cause a regular misfire, rough idle, poor fuel economy, roughness or loss of power (and will register a trouble code that will illuminate the Check Engine light). 10-03-13 08:51 AM - Post# 2387696 I'm having kind of the same problem on my 90 c1500 5. Chevy 350 tbi stalls when warm Chevy 350 tbi stalls when warm. I had veh at my mech at time he had change ign mod etc no change he call GM and they told him change coil in dist. Discussion Starter • #1 • Nov 25, 2010. Problem: Driving along fine all day, pull into driveway and it dies before I can turn the key off. Carbureted or TBI 5. 7L GM engines. The fuel injectors in your vehicle are designed to spray fuel into the cylinders of your engine where it is combined with air and compressed before being ignited by the spark plug to produce power. Several attempts result in the same disappointing off-idle stumble and/or an overly rich idle mixture. A leaking injector often causes a misfire on the cylinder it’s leaking into. 1991 Suburban 350 TBI Misfire The 1973 - 1991 Blazers, Jimmys, and Suburbans Message Board 1991 Suburban 350 TBI Misfire - The 1947 - Present Chevrolet & GMC Truck Message Board Network Register or Log In To remove these advertisements. I would like to ask some of you to take an educated guess at this problem(s). TCS EQ Ratio Minimum: Minimum EQ Ratio when TCS is active. It does it sometimes at idle when cold and does it just going down the road at 40-45mph when it gets into overdrive and is running in the 1500RPM range. Develops misfire on occasion, especially after heavy or wide open throttle. I did a compression test to see if it was the valves or the the pistons. Here are the instructions how to enable JavaScript in your web browser. 7L TBI - Rough Idle/Stalling by AKupNorth Apr 11, 2018 9:16AM PDT Further research indicates it may be the Idle Air Control Valve acting up. Omaha, NE 68134 (402) 393-7888 Mon-Fri: 7:30am-5:30pm. Check the secondary ignition circuit; Plugs, Plug Wires, Coil(s), Distributor Cap and Rotor. If you're questioning what is normal engine noise, I may have the answer. Another code found set in memory with an ignition system malfunction is the P0336. This would require adapting the later ECU connectors to the original harness. 0 Started with rough Idle, 2 ICVs later high RPM starts finally leveled out. If the fuel mixture becomes too lean, "lean misfire" may occur as the load on the engine increases. Tbi for chevy 350 Tbi for chevy 350. 0 289 302 1406 cam camaro carburetor chevy e-street efi ford fuel pump intake intake manifold nitrous performer pro flo rpm supercharger tbi Red - Red. It's fairly significant while cruising at highway speeds 60mph(1600/1700rpms) and under a load it isn't as noticeable. the tach read 0 yes zero and below, llights are dim and driving my tach reads normal untill i slow down the the problem reoccurs. over the past few weeks i have gone on little test drives, turning the timing up a little as seems ness. I have searched the forums and found similar threads but nothing seems to fix my problem. 4L distributor type ignition system. When this occurs, a misfire is likely to happen during vehicle ignition, especially if the motor is revved up, cut and then restarted. How to reinstall the distributor for a General Motors 4. The EGR valve was faulty so I replaced it. If you drive at a constant speed, your car will stutter or slow down, then accelerate normally before repeating the process. 7 liters, of displacement. Find CHEVROLET 5. 7 tbi i have a 95 k1500 5. 8s take to boost much better than the 4. Problem: With the engine running at idle, always when cold, intermittent when hot. I have built several DZ engines for restorations. For the past 8 months now it has been running poorly. Gas that does not contain enough dispersant-detergent additives may result in; deposits building up and clogging the fuel injectors. Chevy 350 tbi bogs on acceleration. Check the ignition and fuel systems. So, bad gasoline in your tank can cause stalling problems in a car engine. Joined Sep 8, 2008 · 323 Posts. Check the pressure at the fuel rail to verify. The local shop said they replaced it, but it doesn't look new. I'm getting a misfire but no light. I had the timing light on it and noticed the flash became intermittent on multiple cylinders. 8906 Maple St. I bought the truck two weeks ago, drove it home from a neighboring city, two highway hours away, no problems. 30 over 350 crank 350 heads light con rods flat top pistons basically a misfire. Any suggestions?. I recommend upgrading to the 1996 Vortec 155lph fuel pump which can support up to 450hp and plugs right into a factory TBI sending unit. Error occured. Either driving around town when the weather gets nicer and/or while wheeling, the vehicle overheats. Acrobat Printable Version. Easy aftermarket upgrades to the 4. Scotty Kilmer. there are also a few relays that are wired in with. I have a 1992 Chevrolet Silverado with a misfire. However, you can do this test when the engine is running to see if a certain fuel injector is getting a signal to fire if the engine seems to be misfire for some reason. The purpose of the MAP sensor is to measure the pressure within the intake manifold relative to the ambient barometric pressure. Frequently, the cause is owing to the intermittent stalling and the cold stalling. 7l V8 Gm Ignition Module Wdelco Est Distributor 811637t. Misfire is a common drivability problem that may or may not be easy to diagnose, depending on the cause. The truck has 190K miles on it and runs fine other than a misfire. i put a 1995 350 tbi in it i changed the tbi gasket and ever since then both of my injectors are ticking. Stepping on the gas pedal and accelerating your vehicle is awe-inspiring, unless you're having problems with your fuel injector. Shows you have a misfire on cylinder 1 and incorrect ratio in gear 2. In 1954, The Hudson flat-head 6 cylinder outperformed all overhead V-8s including Chrysler Hemi. If you are lucky, it is just a stuck PCV, which sometimes can be cleaned, but can be replaced for under $10 in most cars without disassembling anything (valve is at one end of the tube from the engine (often valve cover) to the intake. 00 Add to cart; #CJ258 – TBI KIT: 1972-80 CJ 4. 7L Hesitation, Cuts out, Misfire Posted to GM Driveability on 3/7/2009 23 Replies Thanks for taking the time to read this,your input is appreciated. Too much air flowing into the intake causes the engine to lean out [too much air in relation to the fuel] and misfire. I've been battling a very intermittent "misfire" all season in my Holley HP EFI RAMJET 350 setup. You replace the DPFE sensor by un-bolting it from the firewall with a 10mm socket (unless you have the less common '01 DPFE Sensor), pulling the old one off the rubber hoses, disconnecting the wire harness from it, putting the new one back onto the rubber hoses (the same way it came off), re-attaching the wire harness and bolting it back to the firewall. >I really >think you should say that marine engines are _different_ than automotive. 7 v8 runs perfect. As the problem worsens these cars set random misfire codes in the P0300 range. 2L Emissions Legal $ 1,395. This symptom is caused by clogged injectors, so make sure your injectors are clean. at idle w/ no load the engine runs almost perfectly(has slight misfire). at idle the voltage goes from 12 to 14 just bouncing around , i tryed the the MAF sensor cleaning and it helped somewhat i have already. boat surges and slows or has trouble accelerating over a certain speed. Intake vacuum is created as a result of the pistons pumping and the restriction of the throttle plate. A recent compression test and plug analysis reveals that the bottom. Changed it out and the thing ran great again. Only at www. For a daily driver, I would recommend a bowttie 350 because of parts availability and such for simpler maintenance over the long haul, but an iron engine will require suspension changes because it weighs over 200 lb more. Shows you have a misfire on cylinder 1 and incorrect ratio in gear 2. This is not my rig, as such I don't have photos. Rough idle and hesitation sounded like a vacuum problem, so I checked the TBI. If low, the pump could be dirty or need to be replaced. Truck ran great but nothing was ever changed in 25 years so I figured I would do a little tune-up. My 1995 gmc 1500, 350 tbi 5. 7 liters, of displacement. The things that you may need to look at are: Carbon tracks on the spark plug and spark plug wires (see images in image viewer). I did convert to the TFI cap and wires but that didnt help. could the ignition s. This high resistance causes a very high amount of voltage to be generated from your ignition coil's secondary. Cylinder Misfire, if your head gasket is good and still cylinders misfire then there is a high chance that your valves might be burned since it causes compression loss. General Motors Vortec line of V-6 engines commonly suffer from problems with excessive oil consumption and engine knocking. Gas that does not contain enough dispersant-detergent additives may result in; deposits building up and clogging the fuel injectors. Joined Jan 30, 2007 · 6 Posts. Chevy 350 tbi bogs on acceleration. This calculator is designed to show the different Compression Ratios for different sized engines. GM doesn't use it anymore (too expensive). check for vacuum leaks by spraying carb cleaner on all the vac lines and tbi base. It doesn't seem like it is affecting anything cause it drives fine and revs really fast \015 Own 92 chevy 5 speed 1500, 4WD 4. over the past few weeks i have gone on little test drives, turning the timing up a little as seems ness. It will correct itself after about 5 seconds, can usually correct it a little quicker by revving. So that comment applies to the owner of a 92 TBI 350 Cadillac. '87 Chevrolet TBI 350 runs rough under load. The engine misfires or runs rough when it is fully warmed up at constant speed or stopped and really bad when pulling a load up a hill or when power breaking. It is a 91 chevy truck with the 350 (5. Scotty Kilmer. Misfires when timming advance is connected to ECM, disconnect and misfire go away. Identified by Camel hump symbol. My 91 Silverado tbi miss under load? BAINES48 MEMBER; CHEVROLET SILVERADO (TBI) when under load. This happens ofter when pulling up a rolling. Engine misfire Description: Damaged injection pump or lift pump on 6. The Olds engine and the bowtie 350 that were used in some larger sedans may be an option, for a total conversion project. The EGR valve was faulty so I replaced it. Or, how to frustrate the living shit out of yourself for hours at a time. The 1973–1974 L82 was a "performance" version of the 350 that still used the casting number 624 76cc chamber "2. Come join the discussion about performance, modifications, troubleshooting, maintenance, and more!. Email * Message. Here are the instructions how to enable JavaScript in your web browser. Use carburetor cleaner and a small-bristled brush like a wire brush, toothbrush or pipe cleaner to clean off the carbon from the metal exhaust gas return tube and the gas entry port on the valve (usually the smaller hole with a spring-loaded pin, or “pintle”). I recommend upgrading to the 1996 Vortec 155lph fuel pump which can support up to 450hp and plugs right into a factory TBI sending unit. First off when i got the car running i had the timing light ready so i could check / set the timing to around 10-16 deg BTDC. The engine control module (ECM), also commonly referred to as the engine control unit (ECU) or powertrain control module (PCM), is one of the most important components found on virtually all modern vehicles. 1988 Yj 350 Tbi Swap. The truck has 190K miles on it and runs fine other than a misfire. I know many people who have the symptoms of:boat hesitates when you gun it. I have 1994 Silverado USA show truck 350 TBI, 172,000 miles. ive tuned it up all new plugs wires cap and rotor fuel filter o2 sensor map sensor and cleaned the egr valve and throttle body. I know this has been addressed before but just to throw it out there again. 1991 chevy 1500 350 tbi manual transmission schematic to download pdf Manual motor tbi chevrolet, in that case you come on to right site. So far I've tried changing the spark plugs and wires (cylinder #8 spark plug was cracked), and the dealership I bought it from replaced the cap and rotor and adjusted timing to get it to run well enough to pass emissions, but the miss is still there. TCS EQ Ratio Minimum: Minimum EQ Ratio when TCS is active. This is a video about rough acceleration rough idle low idle and possible stalling. OK guys, I am out of ideas here on this truck. 3 liter S10 idle problem? So when I start it up it idles from 1500 to 2000 rpms in park or neutral. 8s take to boost much better than the 4. A misfire condition can destroy the ignition module. Runs bad about 90% of time. 3L TBI - Idle troubles within the Automotive Support forums, part of the Tech Support Forum category. Modern vehicles are equipped with an EVAP system that works to reduce. Since the idle air control valve is supposed to manage the idle speed of the engine, a bad valve will certainly throw that out of whack. NOTE: This tutorial covers the EGR valve of the 1987-1995 throttle body fuel injection (TBI) system of the 4. As a result eliminating misfire and stalling problems. I have a similar problem horrible sulfur smell and severe sputtering when getting into overdrive. It helps those gases to return to the combustion chamber instead of directing them to the exhaust emission system. I even seafoamed it and it made no difference to the misfire, it did idle nicer though. They have an aluminum piston that has the stepped metering rods hanging on it and a spring under the piston that performs the "power valve" job. TBI: 13: Oxygen Sensor Circuit Open 14: Engine Misfire Detected P0301: Cylinder Misfire Detected P0302: Cylinder Misfire Detected P0303: Cylinder Misfire Detected. It will loose power when at speed and when accelerating. Really, your Silverado will be running rougher at any RPM, but a misfire will be most pronounced at idle. During the misfire event, all the data was fairly normal. Hello Chris,Ontario's boating season is about to launch for another year. The J-Body Organization, j-body. The truck has 190K miles on it and runs fine other than a misfire. When it detects oil pressure in the vehicle, a switch trips and either the light shuts off, or the gauge becomes active. A while back I had bad misfiring (sputter, missing, and stumble) while accelerating and in the last gear under greater load i. What is the firing order for a 1995 Chevy Tahoe v8 tbi 350 motor? The firing order is 18 43 65 72. it did it with my edelbrock 1406 and edelbrock q-jet. Belltech!. Bad coil pack or plugs. 76cc combustion chamber. Like i said take the air cleaner off and remove the fuel line on the left side (passenger side) and start the engine, jump up on the truck and see how much fuel is coming out of the port on the tbi. 1; 2; Next. The canister purge solenoid is an emissions control component that is commonly found on the evaporative emission control system (EVAP) of many modern vehicles. I can get a Edelbrock tbi performer intake and Power aid tbi spacer used in good shape for cheap. Question: My 2002 Town and Country is showing a misfire in cylinders one and four. 7L is a Throttle Body Injection (TBI) or Central Port Injection (CPI) type, both of these have one thing in common: No mass air flow (MAF) sensor. Part Number: MLL-BP3503CTC1D More Detail. The first sign of this situation often becomes a check engine light code P0300 for a random misfire. There could be a leak in the exhaust system, misfire, the faulty fuel injector (too much fuel), faulty fuel pressure regulator (increased pressure), or even a fault in the downstream oxygen sensor circuit. I will try unplugging the knock sensor and see what happens. I have a 1992 Chevrolet Silverado with a misfire. 6 SUMMIT RACING EQUIPMENT TECH (330) 630-0240 FORD IGNITIONS Wiring a Ford DuraSpark using White Wire Trigger. I checked spark plugs and wires and replaced the fuel pump and filter, and none of that helped. Engine Misfire Diagnosis & Fuel (Throttle Position Sensor) - 1994 Chevy C1500 350 TBI Project TBI part 2 the Black Pearl gets up and running HD. Identified by Camel hump symbol. The air/fuel ratio can also be affected by changes in altitude. Next I tried disconnecting my MSD 6A to rule that out and see if there is any difference. The causes of ignition misfire may include: 88 Chevy 1500 350 Tbi. 7L (350CI) Throttle Body Injected automatic with 126,000 miles. #CA/YJ258 – TBI KIT: JP1 Emission Legal Version CARB EO #D452 1987-91 YJ Wrangler 4. It is a 91 chevy truck with the 350 (5. This is a crank sensor code that sets when the crankshaft position sensor reports data out of range to the vehicles main computer or control module. GM doesn't use it anymore (too expensive). It does it sometimes at idle when cold and does it just going down the road at 40-45mph when it gets into overdrive and is running in the 1500RPM range. Just by doing a "compression test by ear" as in cranking the engine with gas pedal all the way down it doesn't sound great but also my battery was pretty much dead so only cranked for a few seconds before I had to give up. Seems to run good under steady state operation with a light load, as soon as you hit the gas quickly, it hesitates and sounds bad. 30 over 350 crank 350 heads light con rods flat top pistons basically a misfire. replace the Cal-Pak. A stepper motor is a device that moves a predetermined amount per electrical signal it receives by whatever device is controlling it. A restriction of 8-10 percent on a single fuel injector can be enough to cause a misfire. Installing distributor chevy 350 tbi. 3/4 ton, 350 TBI engine with 125,000 miles. This is a simple test to tell you if all cylinders are putting out the same amount of power. Re: Mercruiser 5. 350 tbi misfire: Sign In hello, I've got an 89 350 tbi chevy that has a misfire. The motor's stock except for a Holley Street dominator manifold, and a Holley 600 vacuum secondary carb. There should be a decent amount of fuel streaming out, if not, you have a pressure problem. Wednesday at 8:53 AM; NickD; EV Forum. 1995 k1500 5. Tbi for chevy 350 Tbi for chevy 350. 350 tbi misfire: Sign In hello, I've got an 89 350 tbi chevy that has a misfire. Allow the engine to idle for 5 minutes. Depending on who you’re dealing with, the cost of the work can be as low as $50 or as high as $350. 96 Chevy C1500 4. Chevrolet started production on this robust 5. 1991 Suburban 350 TBI Misfire The 1973 - 1991 Blazers, Jimmys, and Suburbans Message Board 1991 Suburban 350 TBI Misfire - The 1947 - Present Chevrolet & GMC Truck Message Board Network Register or Log In To remove these advertisements. no running rough new TCV no change, Went to shop after a week said needed cylinder head work. A misfire condition can destroy the ignition module. I did convert to the TFI cap and wires but that didnt help. Crate Engine, Long Block, 5. The engine is perfect but when i try to accelerate onto plane. Visual inspection will find most vacuum leaks, after that the only thing I know of that works on fuel injected engines is a electronic vacuum leak detector, kind of like a freon leak detector but vacuum leak detectors listen for the high frequency sounds that vacuum leaks make. GM doesn't use it anymore (too expensive). Sudden onset while driving a couple days ago. Idle Air Control Valve (IAC) The IAC valve GM uses for most of their engines is a stepper motor actuated valve. 7L TBI Mercruiser with Bravo 3 drive on a Sig 260. If the fuel system on your particular 4. Recently rebuilt the 454 in my 1990 TBI Burb. it now does it with the Howell TBI kit i just installed today. 8 is around 250-280 hp & 280 tq. 2 p0122 dtc p0452 Changed the sensor, sensor plug and new wires. The ports are simular to the 350 vortec heads. any help? has new fuel filer, plugs and wires, cap and rotor, and new starter. The next day, I ran a few errands, highway, traffic and stoplight driving; again, no problems. 7 350 automatic trans started missing a week or so ago. gmhightechperformance. Looking for help please, 1998 5. The oxygen sensor is one of the most important parts of your vehicle's emission-control setup and was one of the earliest advances in modern sensor systems and engine controls. There are several other things (besides a No Spark problem to a specific spark plug wire) that can cause a misfire condition on your GM vehicle. Knocking problems are particularly prevalent in Vortec engines used in trucks and SUVs built during the late 1990s and early 2000s. The air injection check valves (STANDARD MOTOR PRODUCTS PT#AV7) are common failure - 1988-1998 Chevrolet Pickup. It runs rough at idle, backfires under load or acceleration, surges when trying to hold at 4000 RPM and park. I have an 89 chevy with 200,000 miles on the engine. i've gotta 93 gmc sierra 2500 with the 350 tbi in it. Volvo Penta Mercruiser 454 V8 7. I have the main coil unit, a slave solenoid for the starter, and a 50 amp breaker that is wired to the slave solenoid and the starter. 87 2wd half ton completely stock 305 TBI How can I tell if the system is going from open loop (when cold) to closed loop (after it heats up) did a smog check and came back with high hydro carbon and high co as you would expect to see when cold. Captain Ross, 2009 Trojan Boater of the Year "Viva Mahia" F32 Cummins 6BTA diesels, "Mack Attack" Chaparral 244 Fish, SeaPro 180, McKee 14, Montauk-17. When engine hot on the highway, when second venturi of carb is opened the engine seems to die momentarily. ECT: This table is used to determine the minimum Equivalence Ratio when in open loop mode. 8s take to boost much better than the 4. Does this misfire occur on flat terrain with low engine load and part throttle? Or is it when hill climbing, or coasting, these things will help myself and others diagnose your problem There are lots of folks here smarter at this than me. 7 rough idle problem Hello, I have a 95 GMC Sierra 1500 4x4 with the 5. 88-95 chevy c/k pickups had the 350 TBI and the 96-98 chevy c/k pickups had the Vortec 350, but which engine is better the Vortec 350 or the TBI 350. 3 liter a 350 305 301 or a 260 engine? it would be a 260 a 350 and 305 are Chevy motors. Allow the engine to idle for 5 minutes. A tool for adjusting the TPS Throttle Position Sensor voltage on a KTM and other motorcycles, ATVs, UTVs, and dirtbikes EXC XC-W XCF SXF SX XC, and Polaris Ranger, Sportsman and RZR. You said you know what this was from - please elaborate. It is a 91 chevy truck with the 350 (5. Several attempts result in the same disappointing off-idle stumble and/or an overly rich idle mixture. The carburetor delivers the air/fuel mixture to the engine, and the distributor ignites that mixture within the cylinders. Thankfully, because both of these components are on top of Chevrolet's 350 small-block engine, checking them is quite easy. I would like to ask some of you to take an educated guess at this problem(s). Chevy 383 / 350 HP 4 Bolt Performance TBI Balanced Crate Engine Truck Camaro $ 3,395. P0300 – Random/Multiple Cylinder Misfire Detected; P053A Positive Crankcase Ventilation Heater Control Circuit /Open; PCV Valve Replacement Cost. Engine dies or won't restart when hot (From: Wild Bill ([email protected] '87 Chevrolet TBI 350 runs rough under load. Check out how we eliminate knock retard on a 1987 Buick Grand National and get a few more ponies too. So, wanting to know if anyone used small block headers off a car in these trucks?. I just can't nail down the problem. 350 CHEVY HEADS BEST AND WORST - Duration: OBD1 code 45 TBI GM 87-95 running rich!! Lean, Misfire - Duration: 22:16. First off when i got the car running i had the timing light ready so i could check / set the timing to around 10-16 deg BTDC. Every question thought and help is greatly. A complete tune-up including spark plugs, spark plug wires, distributor cap and rotor (if so equipped), fuel filter, and air filter will go a long way in correcting the most common problems. 7 MPI - Check Engine Code Reset Thanks for the link. The oxygen sensor is one of the most important parts of your vehicle's emission-control setup and was one of the earliest advances in modern sensor systems and engine controls. The air injection check valves (STANDARD MOTOR PRODUCTS PT#AV7) are common failure - 1988-1998 Chevrolet Pickup. One out of five times the idle will seem to fall out when taking it out of gear and coming to a stop. So on average, the total cost of the replacement, along with the labor cost, is $135 to $460. i've gotta 93 gmc sierra 2500 with the 350 tbi in it. I've looked at the Rinda tool before. Your engine has a problem that many people overlook, the distributer gear wears out--especialy after it is removed and put back in--as it was when you had the intake gaskets done. Engine Misfire Diagnosis & Fuel (Throttle Position Sensor) - 1994 Chevy C1500 350 TBI Project TBI part 2 the Black Pearl gets up and running HD. 7L brass contacts premium to reduce the possibility of secondary voltage arcs that can cause an engine to misfire. I have been going round and round on this truck with no final fix. So, wanting to know if anyone used small block headers off a car in these trucks?. I have built several DZ engines for restorations. When I get on the gas pedal, it backfires from the exhaust and the engine and chugs real bad. Of course, this means that the GMC Sierra and Yukon of the same years have the same issues. The first sign of this situation often becomes a check engine light code P0300 for a random misfire. Replaced it, and began to get a backfire through the TBI ONLY under load and. Threads 7. Your fuel injector is the main gas delivery system utilized in automotive engines, but if it's defective or clogged, your ride can have problems starting. Techno’s “Know your car” Series # 10 Mazda MX-5. Tyler's Forgotten Car Rescue How to Fix a Random Engine Misfire in Your Car (Code P0300) - Duration: 2:56. The next day, I ran a few errands, highway, traffic and stoplight driving; again, no problems. I have a 350 gas V8 and in the mornings when I start the engine, I have a slight miss until I put it in gear, then the miss-fire goes away, and the engine runs fine ? I restored the truck over the last few years and I put in a matched set of TBI injectors and an new Edelbrock 3407 TBI intake. Although we're writing about this Chevrolet intermittent electrical problem, the issue also occurs on GMC and Cadillac trucks. 0 289 302 1406 cam camaro carburetor chevy e-street efi ford fuel pump intake intake manifold nitrous performer pro flo rpm supercharger tbi Red - Red. On a stock motor with a mild tune you’re looking at 250 hp & 320-350 tq. Wednesday at 8:53 AM; NickD; EV Forum. The 1973–1974 L82 was a "performance" version of the 350 that still used the casting number 624 76cc chamber "2. If your check engine light is on and the OBD-II scanner reads a P0304 code, use the guide below to address it. Recently I started experiencing backfires on my 454, so the first thing I did is read all the related threads posted on this board, and began checking the recommended items (carb, distributor, vacumn leaks, valve springs, etc). Misfires when timming advance is connected to ECM, disconnect and misfire go away. tech questions about 305 tbi to 350 tbi switch Cylinder 2 misfire code and more. All sensors are tested and verified, all tune up parts are new. revved it up and it. 3 vortec include S10 superchargers or turbo kits. It is a 91 chevy truck with the 350 (5. No vacuum leaks found, cleaned all ground connections. I have a 1991 K2500 with the 5. Electric vehicles, hybrids, and home charging equipment. We have Manual motor tbi chevrolet doc, ePub, txt, DjVu, PDF forms. A broken spark plug. The J-Body Organization, j-body. I am new to this forum and looking for any help on this project. could the ignition s. recommended 350 tbi mods; recommended 454; recommended 305 tbi mods; recommended 4. Idles fine in park but rough in gear. So on average, the total cost of the replacement, along with the labor cost, is $135 to $460. Check transmission fluid level and condition and possibly new plugs. Seeing what your symptoms are though, I'd opt for the following seeing you have a 5. The 92 454 TBI engine I messed with the upper bushing was quite worn and allowed the pickup teeth to touch. 1989 camaro iroc z fuel pressure. Having a problem with the engine. org, is the worlds largest automotive enthusiast group exclusively geared towards the General Motors GM J-car platform including the Chevrolet Cavalier, Pontiac Sunfire, Pontiac Sunbird, Pontiac J 2000, Oldsmobile Firenza, Buick SkyHawk and Cadillac Cimarron. I had the timing light on it and noticed the flash became intermittent on multiple cylinders. Its durable rotating assembly has aluminum pistons delivering a 9. Data logs show no EMI/RFI. But what is a throttle position sensor and how can a bad TPS harm your car? Here's what exactly could affect your car's performance. This got progressively worse until the OBD gave the code P0304 - misfire in cylinder 4. 050 with a 110º LSA without problems on a TBI 350,although 112 would be better. Terminator X and Terminator X Max. Help, #2misfire 91 YJ believe motor is a 94 4. I replaced the plugs, wires, cap, and rotor. An engine's vacuum readings can tell an awful lot about its running parameters, provided you know how to read the gauge in the first place. !HELP! misfire hell 98 Bravada I've been dealing with this for awhile now. This article will help you to understand some of the most common causes of misfires and misfire codes (P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308) on the GM 4. 7 silverado 1500 it runs ruff and stall out at red lights and slow traffic do you think. 1994 k1500 silverado, 5. Idles fine in park but rough in gear. Silverado & Fullsize Pick-ups - misfire without check engine light - I have a 95 Silverado with the 350 tbi. Captain Ross, 2009 Trojan Boater of the Year "Viva Mahia" F32 Cummins 6BTA diesels, "Mack Attack" Chaparral 244 Fish, SeaPro 180, McKee 14, Montauk-17. 7L (350CI) Throttle Body Injected automatic with 126,000 miles. The 1985 Corvette replaced the 205 horsepower L83 engine with the L98 230 horsepower engine with Bosch tuned port fuel injection. expansion of metal parts where bolts/screws aren't tight enough, bre. Hi, I am having a problem with my chevy 350 engine that I just installed back in August. 02" heads but with a Rochester Quadra-jet 4bbl carburetor and dual-plane aluminum intake manifold, the earlier L46 350 hp (261 kW) 350 hydraulic-lifter cam, and 9. Your engine runs lean if your air-to-fuel mixture is too light - this means that the fuel in your ignition chamber is being igniting with too much air or too little fuel. My only issue as present is some misfiring popping through the throttle body. Your engine has a problem that many people overlook, the distributer gear wears out--especialy after it is removed and put back in--as it was when you had the intake gaskets done. Unlike a port fuel injection system, that sprays fuel into the intake manifold runner just above the intake valve, the injectors in this system spray fuel directly into the throttle body above the throttle plate. Although not the original engine, it’s about 18 years old and I recently resealed a good bit of the engine (someone else did the work). Maintenance/Repairs. Difficulty during engine start (especially when hot) A bad fuel pressure regulator can create a difficult to start or 'no start' engine. Customers may complain about a ticking noise, engine misfire and/or SES light. I have both harnesses. As long as I stayed under about 1/4 throttle, it was okay. Clean the return tube and gas entry port. Omaha, NE 68134 (402) 393-7888 Mon-Fri: 7:30am-5:30pm. Hi Guy's, I need some help from you all about a problem ive got, Ive got a 2002 Maxum 2700SCR with a Merc 350MAG mpi, we recently had a service by Southern Marine Services and they also replaced the manifolds, risers & riser blocks. 350: LT1, Cast Iron, B-Body: 14088526: 92-97: 350: LT1, Aluminum: LT1 cylinder heads share the same head to block bolt pattern as the standard small block Chevrolet. The causes of ignition misfire may include: Dirty or worn spark plugs Bad plug wires Weak ignition coil Wet plug wires 88 Chevy 1500 350 Tbi New Plugs And Wires And Fuel Filter. Re: Mercruiser 5. P0300 – Random/Multiple Cylinder Misfire Detected; P053A Positive Crankcase Ventilation Heater Control Circuit /Open; PCV Valve Replacement Cost. For over 45 years, PCM has provided the highest quality, longest-lasting, and top-performing watersports engines available and has become the recognized leader in inboard watersports engines. If this situation occurs, it's likely that the timing chain is damaged and needs to be replaced as. Found the CTS to be bad. The Chevy 350 engine is undoubtedly one of the most popular engines that is still used today. 0 tbi motor has low compression and runs a low operating temp. 7 tbi and i was wondering if there was a 02 sensor in my cat b/c if there is not i would like to take that off and run true duals out my back end. Just by doing a "compression test by ear" as in cranking the engine with gas pedal all the way down it doesn't sound great but also my battery was pretty much dead so only cranked for a few seconds before I had to give up. Running perfect for the past year, then wile sitting at a stop lite after 3. Introduction. Carbureted or TBI 5. Misfire Easy step by step guide on how to troubleshoot and repair an automotive engine cylinder misfire P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and P0308, though 1998 Chevrolet Silverado 5. Truck ran great but nothing was ever changed in 25 years so I figured I would do a little tune-up. 3L Tbi VIN Z 8th Digit Fits 88-92 BLAZER S10/JIMMY S15 224641 (Fits: Chevrolet S10) $599. I have taken it to a half a dozen mechanics, promising me that they could find the problem. First, let's pinpoint exactly what's going on. 7L Chevy 350. This happens ofter when pulling up a rolling. It does it sometimes at idle when cold and does it just going down the road at 40-45mph when it gets into overdrive and is running in the 1500RPM range. Today's computerized engine control systems rely on inputs from a variety of sensors to regulate engine performance, emissions and other important functions. If you drive at a constant speed, your car will stutter or slow down, then accelerate normally before repeating the process. 7L/350 Distributors and get Free Shipping on Orders Over $99 at Summit Racing!. But i did notice they are non restistor style ngk b6es. General Motors Vortec line of V-6 engines commonly suffer from problems with excessive oil consumption and engine knocking. 0 air cold crack hesitate idle intermittent internal intake leak lean misfire miss P0171 P0174 P0300 power rough surge vacuum #PIP3232B - (02/07/2007) Models: 2002-2005 Cadillac Escalade 1999-2005 Chevrolet Avalanche, Express, Silverado, Suburban, Tahoe, Trailblazer. It idles terribly. Identified by Camel hump symbol. For a daily driver, I would recommend a bowttie 350 because of parts availability and such for simpler maintenance over the long haul, but an iron engine will require suspension changes because it weighs over 200 lb more. Go to any dragstrip in America on any given night, and you will see a lot of fourth-generation Camaros and Firebirds. Code 54 5 flashes, pause, 4 flashes. 30 over 350 crank 350 heads light con rods flat top pistons basically a misfire. 3L TBI - Idle troubles. The engine misfires or runs rough when it is fully warmed up at constant speed or stopped and really bad when pulling a load up a hill or when power breaking. Get the job done with the right part, at the right price. It soon recovers generally without stalling. load at idle engine stumbles. Your engine has a problem that many people overlook, the distributer gear wears out--especialy after it is removed and put back in--as it was when you had the intake gaskets done. I have a 1995 k1500 with a blown 305 its a tbi i bought a 97 350 vortec motor what do i need to do to make it a tbi as well will my 305 intake work on the vortec 10 people found this helpful. It is written specifically for MegaSquirt ® or MegaSquirt-II™ EFI users who are new to tuning engine with a programmable controller, and tries to make very few assumptions about what you already know. I have a 1995 chevy k 1500 350 tbi it hesitates when trying to accelerate changed plugs wires cap and rotor it dose have aftermarket tbi and performance intake it dose it hot or cold thanks Posted by midget_85 on Sep 22, 2011. Running very rich, down on power. It helps those gases to return to the combustion chamber instead of directing them to the exhaust emission system. The GM TBI (Throttle Body Injection) system uses a pair of low pressure fuel injectors mounted above the throttle body opening. 350 tbi bad map sensor symptoms. 00 off as a credit towards the repair. 3/4 ton, 350 TBI engine with 125,000 miles. A misfire may occur when your engine is idling, causing a rough or uneven idle. Chevy 383 / 350 HP 4 Bolt Performance TBI Balanced Crate Engine Truck Camaro $ 3,395. The engine may also run well at low speed, but won’t accelerate well. I was thinking about the vacum swith for the front axle. 7 MPI - Check Engine Code Reset Thanks for the link. This is not my rig, as such I don't have photos. This means that if you have to consider using a 4150-style carb it is at the upper limit of airflow for the carb design. It is written specifically for MegaSquirt ® or MegaSquirt-II™ EFI users who are new to tuning engine with a programmable controller, and tries to make very few assumptions about what you already know. Belltech!. Check the pressure at the fuel rail to verify. My 96 chevy 1500 4x4 with a 5. The canister purge solenoid is an emissions control component that is commonly found on the evaporative emission control system (EVAP) of many modern vehicles. Wondering if this could be a pickup coil issue, coil, ignition module or distributor issue?. Ford E-350 Super Duty - Engine is misfiring Inspection - Saint Paul, Minnesota Travis was a great diagnostician and also wise enough to know when not to do something he wasn't equipped for. 03 cavalier 2. I have talked to other mechanics about this and I have changed the timing chain and the flex plate to the trans and the fuel pump, and I still had the noise. It is a 91 chevy truck with the 350 (5. recommended 350 tbi mods; recommended 454; recommended 305 tbi mods; recommended 4. Last year at the end of the season the boat started running bad after running it for about 30 min. Do you have any good news to add to your above article, any new marine friendly TBI products?In '08,I installed a Holley 21-700 TBI with the o2 mounted in the manifold to Holly specs. Tyler's Forgotten Car Rescue How to Fix a Random Engine Misfire in Your Car (Code P0300) - Duration: 2:56. Difficulty during engine start (especially when hot) A bad fuel pressure regulator can create a difficult to start or 'no start' engine. Long story short found the short vacuum line coming out of the throttle body was dry rotted. Chevy 350 Runs Rough Under Load. Signs of bad fuel injectors. 350 tbi misfire 350 tbi misfire.