pacificarage

Sometimes, my car has a surging idle. Usually after I rev it up or as it's cooling down from being driven. My CEL is on but its for another reason (EGR system) and I doubt the two issues are related. At first, I thought it was the Idle Air Control Valve (IACV). I replaced the IACV and the issue remains the same (although, I did buy a used one). Now I know that the IACV will throw a CEL if its bad, but it didnt used to do this until I let my mechanic clean on the valve. So I figured it HAD to be the valve going bad. But you all know how that goes...

Matta1

Try cleaning the FITV (Fast Idle Thermo Valve). It's right under the throttle body, fastened with 3 bolts.

*** How-To*** Clean Your FITV aka Fast Idle Thermo Valve - Honda-Tech
This is a great guide on how to do so.

Many try to replace the IACV, only to find out that the FITV needs cleaning.

pacificarage

i actually replaced it. :/

garrison055

hello i have a 93 prelude si h22a with dc 4/2 headers injen cold air intake. i am having trouble with idle only when i am using alot of power.. windows,moonroof ect. i just replaced the distributor and the battery. i also just had the alternator checked and the timing checked when i went to get it smogged. i am stumped and was wondering if anyone had any ideas?

pacificarage

Perhaps, you have a vacuum leak of some kind.