305 Tbi Rough Idle

305 Tbi Rough Idle

in the chilton book it tells you idle is autmaticly adjusted through the computer so thers not a hell of alot you can do it about it but it says if absolutely needed you can remove this seal behind the stop screw. I found the factory set-up was a bit rich off idle on the 1405, for the 350. It idles smooth. Had this problem for a few years now and finally I want to get to the bottom of it. even when your driving and just cruisin like 30 mph when it. It started running bad all at once. Also, I have taken the truck to the dealer for a diagnostic check. com is a division of Guaranteed Carburetors of Largo, Florida. Two Vacuum tests here show engine running smooth EGR Valve disabled Vs engine running rough EGR Valve disabled. i have a 1989 camaro with the tbi 305 was wondering what could be causing my car to turn over more then usual then starts. What is the firing order for a 1995 Chevy Tahoe v8 tbi 350 motor?. vehicle SPECIALTY FUEL CATEGORY MANAGEMENT HEADER Sub Category. 1) Big vacuum leak somewhere. COM CHEVROLET CROSS-FIRE INJECTION 1982-1984 Model 400 TBI. Different owners seem to describe this problem using a variety of expressions. the "power" also seemed to come in at a higher rpm like the engine would wake up at 4800rpm and pull to redline, where it felt wound out and lifeless before. I have taken it to a half a dozen mechanics, promising me that they could find the problem. Monday, October 5, 1908 DAY -OCTOBER :5 1008- Buy Sell0 ' Rent Exchange ‘ USE TIMES WANT ADS PM0PIE 122 jf ’ Times Want advertisements are 1 t k 1 cent a word each insertion Noth ing received. hey john i stay in indianapolis and have the above rough idle at any rpm below 900 and hard cold start issues with carbureted 1968 307. The cause is often a problem in the idle air control system. it also seems the longer i sit the worst it gets. it idles fairly ok when its warmed up but when its cold it idles like crazy. Car (or truck or mini-van) seems to run ok above 30 miles and hour but once you come to an idle, the engine barely stays running. 4 GSI/DP Volvo Penta, 454 engine 1998 27 foot Doral, well last week I idled out of the bay which it ran just fine for about five miles then I pulled back to do a little trolling, after an hour I decided to pick it up and move to another spot and noticed that I couldn't get on plan or accelerate over 2. Many customers who come to us learn that, despite a previous diagnosis, they don't need a new engine, only certain repairs or adjustments. The TBI system uses an IAC (idle air control) solenoid to control idle speed. 1989 camaro 305 run rough and won't idle. This usually means the engine has an air leak and the PCM is trying to bring the idle speed back down by closing the idle air bypass circuit. My truck is an 87 R10 with the 305 TBI. 3? Unanswered Questions. Was running fine when it suddenly died. 3L fuel injection. First the car info. Again, runs smooth at idle and even Revs smoothly but only when the truck is in park. I tihnk the kit cost me $35 or something and the truck ran alot better afterward. Car (or truck or mini-van) seems to run ok above 30 miles and hour but once you come to an idle, the engine barely stays running. In 1989 the cold start injector was deleted. I have a 91 Silverado K1500 4x4, 5. and came up with this. chevy forum at Car Dealer Forums; Truck runs great, but recently when the engine comes off the enriching circuit. 480 Lift W Lifters. SPARK PLUGS How to Read them (Part 3). I have an edelbrock performer intake and 600 cfm performer carb. when i put it in park or nuetral it idle up but it still lopes. Covers various situations that arise while trying to modify a Tbi motor. I had some idle issues when I tried to rush myself to install the unit. I went ahead and replaced the injectors with the appropriate injectors for a 305 block and both fuel trends stay at 128 now (at least for the 15 minutes I was watching it). Like I said it barely feels like a miss at idle, you really have to feel for it or you wouldn't know it's there. Why does my engine spit or backfire? First off, you need to determine whether it is backfiring out the exhaust or back up through the carb. During idle it would sound as if it were about to shut off but it wouldn't. also before i bothered buying a cone filter for mine, i just left the airbox off for a few days to make sure i liked it. when i put it in park or nuetral it idle up but it still lopes. This page is for information about GM Throttle Body Injection EFI swaps. And the rough idle only happened those two times, after it stalled it hasn't done it since. 480 Lift W Lifters. I rebuilt my throttle body with a kit from Ebay and it cured both problems. OTC3054E 11 Piece Noid Lite Set • Simplest method for eliminating the EFI system or idle air control as possible. 80% of the time people jump to opti's. There should be full vacuum at idle, around 20 inches/Hg on a stock engine. Nd Help: 89 4. I then changed the Ignition module, problem came back after 35 minues of. This guide can help you get those injectors back in shape applying some simple tests you can apply to both TBI and EFI systems. Only seems to be noticeable while in gear at a stop light. I am new to this page and I need some help. 7 TBI bogging down when getting on it - Chevy Message Forum - Restoration and Repair Help I got a 94 Chevy 350 motor it starts fine and runs fine but when I excelerate and give it a lot of gas it bogs down. I am looking for some info for my brother. What I did to try and remedy the situation:. And with a 241-260 duration (at 0. View Full Version : C/K Pages : 1 2 3 4 [5] 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41. In other words, a cam with 230. I'm tired of putting money into this and I really don't want to go threw the process of changing it to a carb. 7 liter TBI engine, HEI ignition with detached coil. Engine Stalls, Misfire Code, & Cylinder Misfire The engine may be stalling because it isn’t getting enough throttle opening. Under high RPM load, the engine continues to pull, but does not feel 100%. i have a 1987 gmc truck witha 305 tbi, stalling alot,especialy when put in gear,replaced many sensors, ecm, etc. They said to spray carb cleaner around the base of the TBI and see if the engine speeds up. I Have Gone Around And Asked A Few Shops About What Could Be Done, And They've Said Vacumn Hoses Or Replace The Computer(Lots Of Money). The motor was built with low end power in mind. The TBI conversion kit for the 4. I have an edelbrock performer intake and 600 cfm performer carb. 3 l v6 standard ,with high idle even after being warmed up. 0 liter V8 engine, it's important to inspect both mechanical and cooling system components. I am thinking of 'scoping the idle speed motor wires, but I don't know what to expect. TBI Idle and Throttle Issues. SPARK PLUGS How to Read them (Part 3). Tuesday I start it up and it started to run fine till i got half-way down the street and it started running rough and died. If all other components of the fuel system are working properly and there is still a problem with the idle speed, the screw may be adjusted. 7 tbi engine idles rough and under a heavy load has no power and you can hear crackling coming out of Loss of power. 3 TBI rough idle & Bogs on accel. This was/is a daily driver 4x4 and a stock late 70's truck motor though, a bit different than our cars. 74 Chevy with 92 carbed tbi 350 Edelbrock 600, stock GM 4 barrel manifold, HEI dist. I then changed the Ignition module, problem came back after 35 minues of. I talked to some folks at work who also play with engines. seconds before starting and then idle high while in park or neutral. There should be less than 1 psi of pressure difference from idle to WOT operation of the TBI unit. Different owners seem to describe this problem using a variety of expressions. Get full 1983 Chevrolet Camaro V8-305 5. Since it only idled badly in gear I figured the transmission could be the problem so next time it does it it'll go back to the transmission shop. I have spent almost $1000. runs down the road great!. The fuel puddling is normal for a TBI. While General Motors had to make some compromises in the initial design, the result is an engine that older car owners can tune to a "sweet spot" between. My friend has a 1991 Chevrolet Silverado pickup truck V8 c1500 5. Re: Ported vs manifold vacuum advance March 22nd, 2012, 02:54 PM OK, so we don't get too far off topic, is the amount of vacuum in ported proportional to the amount of air going through the venturi and effected by such or a manifold vacuum function when the throttle plates start to open and retards was manifold vacuum falls?. The truck has full power while driving. It smells like raw gas, smokes, and has no power to get started from a stop. Idle Return: If the engine is not returning to idle quick enough for your liking or is dropping too quickly and killing the engine then you may need to adjust the rate at which the injection system comes to an idle. GOTO -> ThirdGen FBody TPI Prom ID code reference GOTO -> DIY/EFI FTP Bin Library Lots of. It started running bad all at once. Different TBI ECMs have different wiring pinouts. Rough idle is rough to call I changed my egr, tps, and it ended up being a fuel canister solenoid or Some crazy shit. I'm tired of putting money into this and I really don't want to go threw the process of changing it to a carb. He has an '88 Firebird with a 305 and an automatic. I have a 91 GMC Jimmy which idles horribly (and it has even stalled) when it is cold outside (17* C or less) and it is the first start of the day. 7 tbi engine idles rough and under a heavy load has no power and you can hear crackling coming out of Loss of power. It's idling, and then a little misfire stumble, will idle fine again, few seconds later, another stumble. Tuesday I start it up and it started to run fine till i got half-way down the street and it started running rough and died. 3? Unanswered Questions. 2 Disconnect Timing Jumper at distributor (Tan wire with Black stripe). While driving if you. My 95 Tahoe surges a little at idle. Well, I check it out. I have taken it to a half a dozen mechanics, promising me that they could find the problem. 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. " If turning the ignition on causes IAC to engage plunger fully forward, then there is no purpose in doing what he is suggesting. Engine Stalls, Misfire Code, & Cylinder Misfire The engine may be stalling because it isn’t getting enough throttle opening. Buy right now. If there is an open or short in the idle air control solenoid, wiring or driver circuit, or the idle speed it out of range, it will usually set one or more fault codes and turn on the Check Engine light. I have a 1993 Chevy 1/2ton pickup 2wd with a 5. All TBI assemblies are flow bench tested, calibrated and idle adjusted which makes for easy installation. We usually refer to an exhaust backfire as a "backfire", and backfiring through the carb as "spitting" or "coughing". I agree with Danny on this one. 050 on a TBI will cause the MAP sensor to go nuts because the MAP wants to keep the vacuum within a certain range (which if I remember correctly is 17-19 inches). WHen you open the throttle, its not quite as bad, but at idle it looks like it is puddling up (turning from a fine spray to droplets). timing sets 285/305. The engine, for quite some time now, has had a slight misfire, at idle. Stumbles and runs rough at lower throttle positions (just off idle). Idle Return: If the engine is not returning to idle quick enough for your liking or is dropping too quickly and killing the engine then you may need to adjust the rate at which the injection system comes to an idle. For you GM owners, I've had a 95 Saturn SL, and I currently drive a 95 Chevy Blazer. Hold the EGR valve so the cleaning spray drips away from the electric solenoid and vacuum motor. The calibrator provides a wider pulse width on startup to provide a richer mixture for a cold engine. Here are some: Stalls at idle, stalls when I put the clutch in, stalls when I turn a corner, misfires, surges, no power, cuts out, no power at top revs, runs rough, etc. TBI problems; pushing the front axle way the hell out there; Help diagnose why truck is riding rough? Difference from 01+ Chevy 1500 & 2500 Frames? Engine Swap - 305 TBI to 350 Carb - Wiring - HELP; Best way to. will idle in 3. When it sits overnight I don’t get the rough idle or gas smell with the smoke. Buy Holley 502-6 670 CFM Replacement Throttle Body: Throttle Body Injection Kits - Amazon. 7 liter TBI engine, HEI ignition with detached coil. The truck has 190K miles on it and runs fine other than a misfire. What are my options on performance upgrades with the TBI setup? I have a '94 Siverado 4X4 do they make aftermarket headers for these? And if I install a cam or maybe even a set of decent heads, will the TBI. driving down the road it does fine, never sputters or struggles, but once i stop at a light it starts the rough idle. You could be in a situation where the gasket seals a little better when warm. 8 v6 cause these issues along with stalling at light and when shifting into gear. changed ignition control module, found couple vaccum leaks and repaired. 5:1 compression, 5. My 95 Tahoe surges a little at idle. It seems if the butterfly is closed and not open enough to begin with, the ecm will never find the correct idle. In my 89 TBI 350 I can drive beautiful for 30 minutes, then after a few stop and goes, the idle drops and it almost stalls- then the idle goes high, drops low then stalls. Rough idle Chevy 4. Why does my engine spit or backfire? First off, you need to determine whether it is backfiring out the exhaust or back up through the carb. The fuel puddling is normal for a TBI. Fuel pressure on a TBI unit should stay constant under all throttle conditions. There should be less than 1 psi of pressure difference from idle to WOT operation of the TBI unit. Well, I check it out. Only seems to be noticeable while in gear at a stop light. Chevy TBI Distributor SBC 305 350 BBC 454 88-95 K1500 C1500 Truck Silverado New late model EFI Small Block Chevy V8 5. it idles fairly ok when its warmed up but when its cold it idles like crazy. When attempting to diagnose an overheating MerCruiser 5. 7 V8 and TBI. No matter what you're driving, we have the right Chevy 350 Cam Kit for your automobile. FUEL PRESSUREFUEL PRESSURE SPECIFICATIONSSPECIFICATIONS 2. She is currently having the same stalling issues. And when it comes to older cars and. How to fix a rough idle/clean, replace IAC valve and the P0300 code. We do our best to update these Chevy Check Engine Light codes as frequently as possible. Not that hard for the unit. 1992 camaro rs. 1 has rough idle and exhaust is. We Recently Went Through And Put Brand New Vacumn Hoses On And That Knocked Maybe 200 or 300 Off The Idle, But It's Still High. it idles fairly ok when its warmed up but when its cold it idles like crazy. Direct driven Flex Fan, correct rotation. It started running bad all at once. I had a slightly high idle problem and a rough idle at times. My experience with pumps is they are fine or dead. Order your Idle Air Control Valve - 1AISC00030 today at 1AAuto. If the cap is still there, use a small punch to knock it out. 0L(305CID), 2. IAC Idle air control valve cleaning 87-95 TBI 305 350 Sierra Silverado Caprice It idles alot better and adjusts faster than its ever has but it still has issues. I have changed the idle air valve, the TPS, and the thermostat sensor without any results. I may have to give up on this onenew fuel filter and TBI rebuild and the same thingvery rough running, backfiring badly, and absolutely no powertruck bogs down and stalls when put into gear. If you advance the timing - the idle goes up. 3L fuel injection. My 1986 Silverado C10 with a small block 305 is having a weird misfire issue. Appears a fowled plug or plug(s) on the passenger side was the root-cause. I have a 1992 Chevy 1500 two-wheel-drive pickup with the 5. Buy right now. my question is will a combination of a toque converter out of a v6 700r4 stall be too low (1000-1100) a oem alternator from 3. Problem CONDITION POSSIBLE CAUSE CORRECTION 7) Idle cut-off solenoid not working. After the engine warms up to normal operating temperature it runs fine. The vehicle ran perfectly as long as it wasn't idling. Disconnect power from the ECM for at least 10 seconds to clear codes (in case any are present) and reconnect the IAC electrical connector. I own a 1987 Chevrolet R10 pickup with a 5. 5 volts with engine running at idle. One of the most common symptoms commonly associated with a problematic idle air control valve is irregular idle speed. These components are not interchange able between 5. 3 Start and idle the engine until coolant reaches normal operating temperature. I dont believe it would be a vaccuum issue in my opinion if it is running rough at idle. Rough idle and hesitation sounded like a vacuum problem, so I checked the TBI. it just has that low end stuuter. First, let's pinpoint exactly what's going on. When I put the car in drive and get down the road 100' or so, it starts missing, and if I give it a lot of gas it backfires through the carb. Why does my engine spit or backfire? First off, you need to determine whether it is backfiring out the exhaust or back up through the carb. Under high RPM load, the engine continues to pull, but does not feel 100%. The oil sending unit shouldn't make the car stall. IAC Idle air control valve cleaning 87-95 TBI 305 350 Sierra Silverado Caprice. I am looking for some info for my brother. 0L Mercruiser stalling at idle on Muffs: 51: Mercruiser 4. The engine, for quite some time now, has had a slight misfire, at idle. In 1989 the cold start injector was deleted. 0 tbi firebird--- installed a 350 with minor head work, 10-1 compression and a decent cam. 0L VIN E TBI. I figured this might be a vacuum leak but im not sure sure how to check if it is and where to look(how to find the leak). I talked to some folks at work who also play with engines. 7L V-8 and an automatic. WHen you open the throttle, its not quite as bad, but at idle it looks like it is puddling up (turning from a fine spray to droplets). CHEVYTHUNDER. I didn't have a chance to actually drive the vehicle because of insurance/car being garage stored during the winter. I have an 89 firebird with 305 tpi. Connect a vacuum tester (Mityvac) to the line leading from the TBI unit to the front (single port) side of the solenoid. I tihnk the kit cost me $35 or something and the truck ran alot better afterward. years ago the idle was adjusted for my grandma when it was her car because it was stalling in the winter. One of the most common symptoms of a clogged fuel injector is a rough engine idle. Information that addresses safety, reliability, performance and comfort related problems with Chevrolet Camaro V8-305 5. 7l Vortec Tbi. 1990 chevy truck 350 tbi runs rough at idle up and down and exhaust stinks bad, bad gas milage too - Answered by a verified Chevy Mechanic I swapped a 305 to a. While General Motors had to make some compromises in the initial design, the result is an engine that older car owners can tune to a "sweet spot" between. Roller Lifters And Pushrods Set For 1987-2002 Chevrolet 305 350 5. 7L TBI - Rough Idle/Stalling by AKupNorth | April 10, 2018 12:56 PM PDT (Let me try again. I have a 91 broughm with the 305 (5. A few days later it began to stumble and hesitate upon acceleration. My 99 silverado has a 4. If the EGR valve is stuck open due to a carbon chip you will notice rough running at idle and low speeds when it is supposed to be closed, but it normally opens at higher speeds. Shop safely with us online or call 888-844-3393 and buy the quality part your car or truck needs today. 7 efi in it and i had the same problem, i ended up having to advance the timing on it, which i did just by turning the distributor cap a little bit and listening to. This guide can help you get those injectors back in shape applying some simple tests you can apply to both TBI and EFI systems. when i put it in park or nuetral it idle up but it still lopes. Got the parts together and the swap began. Under high RPM load, the engine continues to pull, but does not feel 100%. A friend has an 87 4wd with a TBI 305. it also seems the longer i sit the worst it gets. The truck has 190K miles on it and runs fine other than a misfire. It idles rough for about 20-30 seconds (longer when colder) then smooths out to a normal nice smooth idle. Chevy TBI Distributor SBC 305 350 BBC 454 88-95 K1500 C1500 Truck Silverado New late model EFI Small Block Chevy V8 5. S19, and other EFI info/files GOTO -> Ludis' C3/P4 ECM reference Lots of great info on C3 and P4 ECMs. You shouldn't feel it there. Car (or truck or mini-van) seems to run ok above 30 miles and hour but once you come to an idle, the engine barely stays running. Mercruiser EFI Stalling and Surging Symptoms at Idle in the fact that only marine tbi uses 30lbs did he use the exact right spring automotive tbi use's 12 i think. In my 89 TBI 350 I can drive beautiful for 30 minutes, then after a few stop and goes, the idle drops and it almost stalls- then the idle goes high, drops low then stalls. I have a 91 GMC Jimmy which idles horribly (and it has even stalled) when it is cold outside (17* C or less) and it is the first start of the day. 562 114 LSA. this is a 1992 Gmc sierra 305 TBI. We offer a plethora of Chevy 350 Cam Kit for your vehicle needs. 0L VIN E TBI TSB (Technical Service Bulletins Chevrolet Camaro) and Automotive Recalls. What is the correct idle on a 1991 Chevrolet Camaro with a 305 TPI 1991 camaro rs v-6 3. from a 305 or 350 V-8 engine to replace your existing 2-barrel or 4-barrel carburetor. I hooked up my scanner and went through the engine data and saw the O2 sensor on B2S2 was showing a mV of 4 while every other sensor was floating around 400-700 at idle. ok well car has new-fuel filter cap rotor plugs o2 sensor tps wires car is only sputtering on low rpms. When I come to a stop the idle is off, it almost feels like it is mis firing. rpms go from 300-1100 The colder the weather the worse it is. First the car info. if its a 350 tbi then it could be the idle air control sensor. 480 Lift W Lifters. Engine performs great otherwise. when trying to rev, engine sounds like it's bogging down. He has been to numerous mechanics in Jacksonville and they all want to replace the idle control valve, this has been done twice now. I managed to fix the idle by cleaning and readjusting the IAC valve, and the rough shifting seems to have been because of low fluid. check 1st spark plug on either side of engine and they look good. So I have an 87 Silverado half ton. 565 111 LSA. Looking to buy Chevy Engine Pro? We feature a huge array of chevy engine pro and other relevant listings. 7 efi in it and i had the same problem, i ended up having to advance the timing on it, which i did just by turning the distributor cap a little bit and listening to. The car idles smoothly at 900 RPM in Park or Neutral once its warmed up. At low RPM, seems to have sluggish response with light throttle pressure, after a little more gas kind of "jerks" and goes. Well, I finally found my intermittent idle issue. also before i bothered buying a cone filter for mine, i just left the airbox off for a few days to make sure i liked it. Designed for small and big block standard deck Chevy V8, this unit replaces and upgrades stock High Energy Ignition distributors found in 1987-1993 car and 1987-1995 truck external coil applications. Also stumbles and occasionally will stall when first started in the morning. It's idling, and then a little misfire stumble, will idle fine again, few seconds later, another stumble. when i put it in park or nuetral it idle up but it still lopes. 035, if those all check out, i would look into your timing. Curing Rough Idle. 7l engine with tbi. Chevrolet SBC Chevy Engine Pro Very Rough Idle Stage 5 HYD. While General Motors had to make some compromises in the initial design, the result is an engine that older car owners can tune to a "sweet spot" between. The best and easiest way is to purchase a "SCAN" tool like Diacom or Turbolink and they will conveniently read and store the code for you. We Recently Went Through And Put Brand New Vacumn Hoses On And That Knocked Maybe 200 or 300 Off The Idle, But It's Still High. I have taken it to a half a dozen mechanics, promising me that they could find the problem. How to cure rough- and/or high-idle issues in your driveway. They said to spray carb cleaner around the base of the TBI and see if the engine speeds up. The truck has full power while driving. I have a 91 GMC Jimmy which idles horribly (and it has even stalled) when it is cold outside (17* C or less) and it is the first start of the day. We've got a '95 K1500 pickup with a TBI 5. I'd be looking at valves that need adjustment, a bad injector, or an ignition problem for a single cylinder. I have a 90 Chevy 2500 , 5. If there is an open or short in the idle air control solenoid, wiring or driver circuit, or the idle speed it out of range, it will usually set one or more fault codes and turn on the Check Engine light. Occasionally, though, buildup from impurities in the fuel, or injector system electrical or mechanical problems may contribute to rough idle, misfires, harmful emissions, poor engine performance, and fuel economy. 7l engine with tbi. S19, and other EFI info/files GOTO -> Ludis' C3/P4 ECM reference Lots of great info on C3 and P4 ECMs. I have taken it to a half a dozen mechanics, promising me that they could find the problem. 8 v6 cause these issues along with stalling at light and when shifting into gear. We certainly understand how frustrating it can be to look for a code definition and have it not online when you need it. Stage I--Mild 305 ci. Rough idle? A good dousing with throttle body cleaner may be enough to restore your EGR valve to near-mint condition, transforming a harsh idle into a soothing hum. Chevy TBI Distributor SBC 305 350 BBC 454 88-95 K1500 C1500 Truck Silverado New late model EFI Small Block Chevy V8 5. You shouldn't feel it there. At worst it will cause a hesitation or stumble on acceleration. - done all the basics and even replaced the idle valve - but still the idle is too high - Cheyenne P/U 1989 - 305 small block with TBI injectors. I figured it was time for a tune-up, replaced plugs and wires. Fuel injector symptoms for bad, faulty, dirty, clogged, leaking injectors: poor starting, idle, performance, fuel consumption, failed emissions, detonation. looking for any input on tuning info to make this thing not run rich and stall at idle--- car was a 5. Well you've got a Chevy TBI motor, and I assume you've pulled DTC's through the Climate Head, so why don't you try it my and see if it works? I can't really see them changing the diagnostic wiring on the 91 and 92, just because it got a TBI engine. Setting IAC (Idle air control) valve I saw this video , and wonder about his words of "wisdom. But the 93, with the same engine can only be diagnosed through the climate control. The GM TBI (Throttle Body Injection) system uses a pair of low pressure fuel injectors mounted above the throttle body opening. It smells like raw gas, smokes, and has no power to get started from a stop. It idles rough, at different speeds and never settles down, (between 900 and 1300 rpm. 480" Lift 232°/232° SB Chevy 283 305 327 350 400 HP Cam Lifter Zinc Kit. Surging idle can be caused by a number of different problems. Problem: With the engine running at idle, always when cold, intermittent when hot. Even though the timing has nothing to do with engine run-on, (because the key is turned off and "ignition timing" is no longer in play), timing DOES affect the engine's idle when it's running. 050) camshaft, you'll have a rough idle, low manifold vacuum, and need 3. Is the TPS bad? How about the IAC? It appears that too much fuel is dumping into the throttle body during idle and it seems like it is flooding. I figured this might be a vacuum leak but im not sure sure how to check if it is and where to look(how to find the leak). How to fix a rough idle. I've replace oxygen sensor, throttle body injectors, fuel regulator, idle control valve, dist cap, dist module, rotor button, pick up coil, thermostat, and new coil. Hi, I am having a problem with my chevy 350 engine that I just installed back in August. At worst it will cause a hesitation or stumble on acceleration. Working on the rough idle problem When we were in town yesterday I purchased a new PCV valve for the van's engine.