So here's the deal.... I have a rough idle - no hunting, just rough. When I start the car for the very first time of the day (and that's the only time all day) it fires up to about 2000 and then immediately drops to about 400 - almost stalls, then jumps back up to about 1800 and gradually idles down to about 800 (in Park) as it is supposed to.

I decided to set the IAC as per the proper procedure, and this is what I found: I adjusted the idle to about 500 with the IAC disconnected, then reconnected the IAC and fired her back up again. At first, the idle seems proper at about 800 or so (I have the digital dash so it is hard to be really accurate with the rpm). However, after about 30 seconds the idle dropped off - right back to how it was with the IAC disconnected. I tired this a couple of times with the same result... good idle speed for a bit and suddenly it just dropped way off, and of course it gets even rougher when it's that low.

Even when it is idling "properly" for those few seconds it is rough, but I think I need to find out first if my IAC needs to be replaced, then move on to the TPS.

Thoughts, help, advice??

Thanks

Eric

 

Anyone??

 

i had close to the same problem for a while

when i start it in and wheather condition it would rev up to 2500 then slowly go down to 600-800 in park and when i would put it in drive it would idle very rough at like 500

the the problem with when you would adjust the idle with the iac disconected and it would idel fine then go right back

i had all the same problems

i changed the iac and it did not help at all
i spent a whole day adjusting the iac and the tps with no avail

then i said thats it and i baught a timeing light at unpluged the thin tan timeing wire on the passager side of the engine conpartment , started the car and read my timing and it was 3deg after top dead center and it is sapposed to be 6 deg before top dead center

i was in shock it was 9 degs off
i was wondering why this was because when i first got the car it ideled fine with no problem then my father told me that when he had all him old camaros and gtos that after a while of a car geting beat on that the timing chain would streach over time
so i set my timing to 7 degs btdc and started the car and it ideled much better but not as good as i hoped but after time the computer releared the spark and fuel tables and now the car runs great with no surging, rough idel nothing
i have my idel set so it runs 1000 in park and 700 in drive

get a timming light or bring it to a good mechanic

hope this helps