another noob question about rough idle
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another noob question about rough idle
I have an 02 vert, auto, with 75,000 miles. About 5000 miles ago my car started to idle a rough. No codes, and have since poured some good money into ruling out what ISNT the problem.
Things i have had done so far. Changed plugs, wires, fuel filter, had injectors flushed, then had them pulled and rebuilt. replaced air filter, cleaned MAF, Checked all seals coming from intake to throttle body. pulled the throttle body off and cleaned it, replaced the pcv valve. replaced 2 o2 sensors. Ran several bottles of techron through the system to clean it before i had the system rebuilt.
My Thoughts are that maybe its a vacuum leak. i dont know for sure and i have only checked the vacuum port coming out of the throttle body where the pcv valve is connected. Is there somewhere i can test ALL the vacuum lines at once? Does the 02 have an egr valve? i have seen mixed answers to maybe it doesnt and some saying it does. Also, any other thoughts as to what this dang idle issue could be? i have had it hooked up to a real time scanner and still nothing appears out of the ordinary.
Things i have had done so far. Changed plugs, wires, fuel filter, had injectors flushed, then had them pulled and rebuilt. replaced air filter, cleaned MAF, Checked all seals coming from intake to throttle body. pulled the throttle body off and cleaned it, replaced the pcv valve. replaced 2 o2 sensors. Ran several bottles of techron through the system to clean it before i had the system rebuilt.
My Thoughts are that maybe its a vacuum leak. i dont know for sure and i have only checked the vacuum port coming out of the throttle body where the pcv valve is connected. Is there somewhere i can test ALL the vacuum lines at once? Does the 02 have an egr valve? i have seen mixed answers to maybe it doesnt and some saying it does. Also, any other thoughts as to what this dang idle issue could be? i have had it hooked up to a real time scanner and still nothing appears out of the ordinary.
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Also another thing, i dont know if its related, if its not just disregard it but my engine temps have been staying in the 220 230 range alot lately, i flushed the coolant and put in some wetter temp reducer in it but still it stays really warm. before i flushed it tho i was getting into the 230 240 range regularly
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St. Jude Donor '15
in what kind of driving conditions? what outside temps?
in stock form the fans don't come on until some ridiculous temperature like 220'ish? so that couldn't be helping
for me, cleaning out the radiator fins made a night/day difference. a new thermostat/reprogramming could help as well
in stock form the fans don't come on until some ridiculous temperature like 220'ish? so that couldn't be helping
for me, cleaning out the radiator fins made a night/day difference. a new thermostat/reprogramming could help as well
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outside temps have been as low as 70s driving conditions are just around town, city driving. when i get into the 220 230 and upwards of a hundred when it hits 240 ish. So that makes me worry less about that, i will check the radiator when i get home and clean it.
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From: Raleigh, NC
St. Jude Donor '15
i had to pull the radiator and use compressed air to really get it clean
it's also possible some trash like a bag or something has gotten in there while driving. it's damn near impossible to see without pulling a few things apart and even harder to clean.
gl though. it's a pretty common issue.
it's also possible some trash like a bag or something has gotten in there while driving. it's damn near impossible to see without pulling a few things apart and even harder to clean.
gl though. it's a pretty common issue.
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From: Dyer, IN
I have an 02 vert, auto, with 75,000 miles. About 5000 miles ago my car started to idle a rough. No codes, and have since poured some good money into ruling out what ISNT the problem.
Things i have had done so far. Changed plugs, wires, fuel filter, had injectors flushed, then had them pulled and rebuilt. replaced air filter, cleaned MAF, Checked all seals coming from intake to throttle body. pulled the throttle body off and cleaned it, replaced the pcv valve. replaced 2 o2 sensors. Ran several bottles of techron through the system to clean it before i had the system rebuilt.
My Thoughts are that maybe its a vacuum leak. i dont know for sure and i have only checked the vacuum port coming out of the throttle body where the pcv valve is connected. Is there somewhere i can test ALL the vacuum lines at once? Does the 02 have an egr valve? i have seen mixed answers to maybe it doesnt and some saying it does. Also, any other thoughts as to what this dang idle issue could be? i have had it hooked up to a real time scanner and still nothing appears out of the ordinary.
Things i have had done so far. Changed plugs, wires, fuel filter, had injectors flushed, then had them pulled and rebuilt. replaced air filter, cleaned MAF, Checked all seals coming from intake to throttle body. pulled the throttle body off and cleaned it, replaced the pcv valve. replaced 2 o2 sensors. Ran several bottles of techron through the system to clean it before i had the system rebuilt.
My Thoughts are that maybe its a vacuum leak. i dont know for sure and i have only checked the vacuum port coming out of the throttle body where the pcv valve is connected. Is there somewhere i can test ALL the vacuum lines at once? Does the 02 have an egr valve? i have seen mixed answers to maybe it doesnt and some saying it does. Also, any other thoughts as to what this dang idle issue could be? i have had it hooked up to a real time scanner and still nothing appears out of the ordinary.
Stop changing parts, and get on some serious troubleshooting. You need to determine the condition of the motor, and have someone put a tech II or tuning software on the car to monitor events in real time.
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As for condition of engine it seems ok, havent had any other problems, and i have had a friend at my local tunex plug their tech2 (or some kind of real time scanner) in to look at lean and rich mixtures and MAF operation and such like that, nothing appeared out of the ordinary. There was a history code for a MAF sensor issue but that was before i owned it. Im not really sure if its missing or bogging, its quick when i get on the throttle, doesnt seem to be bogging on hard accel, power and gas mileage is still great
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As for deep pockets, im a college student with a prego girlfriend and barely payin my bills due to hours cuts. my pockets arent deep im just barely stayin afloat. What other trouble shooting can i do, a real time scanner was unable to pick anything up unless the mechanic didnt know what he was looking for.
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it might be idling to low, dont remember what it idled at before, never payed attention till the problem started. it isnt hunting for idle, the rpms are dead steady, it idles now at like 600 or 700. Also a video wont help i dont think as to this is just causing the car to physically shake and buck ever so gently, not really any odd noises. if a video will still help im glad to post one tho
Last edited by jonwymore; Aug 19, 2009 at 12:13 PM.
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As for deep pockets, im a college student with a prego girlfriend and barely payin my bills due to hours cuts. my pockets arent deep im just barely stayin afloat. What other trouble shooting can i do, a real time scanner was unable to pick anything up unless the mechanic didnt know what he was looking for.
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If you've hit the obvious stuff like plugs, wires, etc..then it's time for a closer look. Like you've already stated, vacuum is a good place to look..inspecting for security and cracks in lines, etc. A tech II can read cylinder events in real time to see if there is a low idle miss, but not bad enough to generate a code. This will help you isolate to a cylinder.
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Here is another piece of odd info regarding the problem. most times i make a change to something like when i replaced my o2 sensors, or replaced the pcv valve it seems to stop for the first couple miles, just long enough to get my hopes up that i fixed it and then BANG it comes right back and i slouch down in my seat and turn the bass up so i can tell the difference between bass beats and the idle issue lol
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A few things - take your time with then and don't rush through them:
- First, the stock LS1 has a characteristically "shivery idle"....not rough but shivery......another way to describe it is stable RPMs with a slight "tremor". I have a 2001 LS1, A4 and it idles nicely at 500 RPMs in drive when warm. Are you sure it's just not shivery?
- Second, check the alternator. The clutch pulley on the front of mine cracked and it made the car idle rougher along with a deep but muffled rattling noise. I know, hard to believe but true.
- Third, check the water pump to make sure the pulley is turning freely & doesn't feel like it's grinding........if it is, that could cause some roughness & vibration.
- Fourth, check the belts, if they are older & dry, they will cause more noise & vibration.
- Fifth, check the belt tensioners/pulleys & idler pulleys to make sure they are keeping enough tension on the belts and that the pulleys are turning freely..........the bolt on my main serpentine idler pulley was slightly loose.
Once I had these things squared away, people at work have commented on how quiet my car is as it's idling in its parking place.
Good luck !
- First, the stock LS1 has a characteristically "shivery idle"....not rough but shivery......another way to describe it is stable RPMs with a slight "tremor". I have a 2001 LS1, A4 and it idles nicely at 500 RPMs in drive when warm. Are you sure it's just not shivery?
- Second, check the alternator. The clutch pulley on the front of mine cracked and it made the car idle rougher along with a deep but muffled rattling noise. I know, hard to believe but true.
- Third, check the water pump to make sure the pulley is turning freely & doesn't feel like it's grinding........if it is, that could cause some roughness & vibration.
- Fourth, check the belts, if they are older & dry, they will cause more noise & vibration.
- Fifth, check the belt tensioners/pulleys & idler pulleys to make sure they are keeping enough tension on the belts and that the pulleys are turning freely..........the bolt on my main serpentine idler pulley was slightly loose.
Once I had these things squared away, people at work have commented on how quiet my car is as it's idling in its parking place.
Good luck !
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Ok so i checked all of those things and all appear ok. I have been doing some research and found conflicting reports about an egr valve. Im somewhat convinced this problem is coming from a vacuum leak and i want to test it and thought about replacing the egr valve and found the part on auto zone however alot of posts im finding state that an 02 doesnt have an egr valve. Which leads me to 2 questions, 1. Why would autozone as well as other parts stores sell a part that doesnt exist. and 2 where besides the vaccuum port where the pcv valve goes into the intake can i test the vacuum system. Any one with good pics or a good how to?
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Because the part does exist for an F-body. You can't rely on the parts guy at Autozone to know your car....that is the owner's responsibility.
You can test it with a tee fitting at the brake power booster line....I don't have any "how to" info. I still think you need to get your car to a mechanic that can read all the sensor in real time to assess the issue. Since you said it runs fine initially, it sounds like closed loop issue.
Safety Car
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From: Lacombe Louisiana
I would focus on your high engine temps first as that can cause all sorts of idle problems.Though if you have no misfire or MAF codes you may not have a problem at all and you are trying to correct a normal idle quality.BTW does you engine ever stall at idle?