so i see a ton of these threads hell i've made one myself. and honestly I work 12 hours a day mon-fri I do not feel like searching them all.

SO if everybody on here who's every had an idling problem and fixed it please describe it and how you fixed it.

IF NOT just please list the common idling issues and their resoloutions.

if it helps i have an 85 305 TPI i just got runnin today. it drives awesome has tons of power but feels like it could and should have more. for one i have no muffle right now it rusted off. when it's idling though it is so squirly.

 

on a stock vehicle, all that is needed for a good idle is to make sure all parts are in good order. this means:

1)ALL regular wear items AKA tune up parts taken care of. oil, oil filter, pcv system, air filter, vacuum lines!, and the complete ignition system and fuel system, all gotta be a-okay.

2)all sensors need to be working and in their correct ranges, this means (on tpi) your minimum air settings being correct, your iac being clean and set, the timing being checked and matched to the setting in the prom, or very close to it if you can't diy tune(which you should if you plan on using tpi) and the tps voltage should also be set.also the electrical connections should be gone over. as well, these cars aren't young.

3)speaking of electrical, the charging system is very sensitive on 3rd gens and should be a top priority, do whatever you gotta do, get constant and reliable voltage, or find out where it's going. voltage at the battery directly affects air to fuel ratio so low voltage can cause all sorts of odd problems, if you've done the first two items, i bet your voltage will be fine. mine just got alot better by replacing my worn out plug wires, can dump alot of voltage out of leaky wires!

4)for maf cars, make sure there are no leaks for airflow after the maf, bad business and affects idle quality greatly.


if you're stock or close to it i'd be surprised to see idle problems after this checklist, it's possible but not probable.i can't think of anything i'm missing here, anyone else?

 

Well. I just fixed my idle problem that ive been chasing all summer. When the engine is warm and has been running for about 1/2 hour the idle would lope consistantly. especially at a stop. sometimes enough to stall the engine if i didnt set the idle high to begin with. my fix was new fuel injectors. i must have had one or more leaking enough to cause a rough idle. I ohm checked each injector in order to troubleshoot them. engine runs great now after the swap.

 

I too am having idle problems, I found a tuning artical that states to set minimum idle http://www.diy-efi.org/gmecm/papers/tunetip.html#idle, I followed that but I hear the iac hissing, making me believe that the idle is set too low, I have adjusted it up and sounds better but still rough idle. I will get new plugs, wires but what should the voltage be at the battery? 14+-?

 

My rough idle problems came from a very sneaky culprit.. a loose IAC and then the rest was resetting it since i had it idling high.Also cleaned my throttle body,ohm tested each injector,check fuel pressure at the rails,double check timing,spark plugs and vacuum leaks all lead me to solving mine once and for all.

 

i have an 89 Iroc Z28 w/ a 355 tpi..I still have an idle problem, but its just staying low and it dies off after a few seconds.. occasionally it will sit by itself and idle but randomly, (and most of the time) it wont idle without my foot on the gas.. but highway driving is fine. would a vacuum leak between the motor and tranny mess with the idle and mess with how late my tranny shifts? i do have a stage 2 shift kit but at normal/average acceleration it seems like it won't get enough pressure to shift until about 2500 rpm.. any ideas???

 

I developed an idling problem after I swapped out the auto for a T5. Very strange, it runs great just won't idle.

when I come to astop the idle steps down (IAC), hovers at around 650 rpms then the car just dies.

Was thinking it was the TPS but have not checked voltage yet.

 

I did not find out my problem, rough idle and running rich. I have since pulled the motor and installed an engine from a 1979 truck. I will then have the block and heads checked for cracks and wear, then replace all bearings and gaskets. I want to find a car to instal this back into so if I have issues, at least it won't be my primary ride!