I think that my IAC is going out. When I first start the car, it revs to between 2 and 3 grand for about 5 seconds, and then drops down to around 800. The idle isnt steady either, especially once it warms up. My friend had the same problem with his thunderchicken, and a IAC fixed the problem. Any ideas? Thanks.

 

check to see where your TPS is set at

 

Have you tried cleaning the IAC? My '92 GT used to have idle problems in the morning until i finally cleaned the IAC and now, no more of that b/s. Just add soap, water, and brush. But i did find out that after awhile, no matter how much you clean it the idle is still jumping around because of the motor in the IAC, so you may end up replacing the whole thing eventually.

 

unplug it, if the car runs differently, its the IAC

 

sounds like my problem, but unfortunetly I have to wait for a battery to check mine. Someone loan me their battery.

 

Bobby- what should I have the TPS at, and how do I check it? And yes, I have tried cleaning it. It ran good for about 2 hours, and then back to the same old crap. I was afraid of it being the IAC. It looks like the one for my friend's thunderchicken. If it is, its about a 60 part. That sucks

 

THe TPS should be at .98 - .99 and make sure you set the idle screw right too

 

no need to mess with the idle screw unless it doesnt idle high enough... if your surging then yea clean / replace the IAC and check the TPS, around .98v for best performance like they said... check it KOEO. 9 out of 10 its either the IAC or TPS with surging probs.

 

get yourself a voltmeter and set it to DC. then attach the red wire (positive) to the green wire coming out of the TPS. you wil have to puncture the skin to do this. then the black (negative) wire to any good ground. loosen the two screws and turn it till it reads .98-.99volts. then tighten it back down. check it one last time to make sure it didnt move. do all of this with the key on, engine off. ( KOEO )

 

I'm having about the same problem, when i first start her up she starts fine, revs to about 1500 for a minute, settles right down to about 800rpm and then when it gets warm the idle gets rough and surges, the TPS is set properly.

When i unplug the TPS it gets worse, when i plug it back in, it gets a little better, NOW when I unplug the IAC the car just shuts off[&:]

I have a new IAC valve at home and i was getting ready to take it back, does this sound like the same problem??

IF so, i'll replace that turd in a heartbeat.