Dr.T Sanchez

Ok so i have been fighting this for a while now, bought two new IACs and both when installed produce an insane high idle. However i was told that it was because i have a vacuum leak, i have chased down every possible way and found one way it could leak and taken care of that but it still jumps all the way up to 2500 then drops to 1500. Now i have had my ac disconnected for some time but when i plug it back in it jumps to 2500 then back down to 1500 then stalls. Ive replaced the TPS sensor while i was at it as well, also unplugged the battery and yadda yadda yadda.

I have the old one on for now but the surging is driving me mad and have already took the vacuum lines out and checked for a leak via a cigarette lol.

cliffyk

Have you checked the throttle stop screw setting? If it is improperly adjusted the idle can behave as you describe--here is the procedure.

It can also be caused by a stuck PCV valve...

Dr.T Sanchez

Set screw has never been touched for fear i would mess something up and the pcv was replaced maybe 5k ago

cliffyk

That's interesting, however have you checked the throttle stop screw setting?

That it has never been "touched" does not mean it has not shifted or opened up from vibration and wear--in fact it is a good reason to check it...