ok, whats up g2ic, i bought my 91 gs DA and it had a really bad idle surge, its would go from 3-2.5k or 3-2k rpm then when i would drive it for a while it would drop to 2k-1.5k and start the bounce then if im really driving and its 100% it stops and idles at 900 where it supposed to be, but if i drive it alittle hard after it will start bouncing again, i cleaned my iacv last night and turn the dial with a flat head on the throttle body but no dice, what should i do next? this gets really annoying and it also take a long ass time to warm up like ill start my car and it will start at 3k and stay there for 20 minutes then idle bounce
with a 98 b18b swap
when you attempted to adjust the idle, did you do it with the iacv disconnected?
try that. then, check for vac leaks
I cleaned the iacv and I don’t think I have any leaks because I don’t hear any high pitched squeaking noise, and I tried to adjust the idle with it on, I did improve after the cleaning, it starts at 2 and goes up to 2.5 then bounces to 2 and drops to 1.5k
What about the fitv?
follow the procedure for adjusting idle. you have to disconnect the iacv when you adjust. otherwise the ecm will just command the valve to counter your adjustment. also, you won’t necessarily hear a vac leak.
and yes, it could also be the fitv. to check, remove the air cleaner boot and start the car. engine at operating temp, you should feel no suction from the fitv port at the throttle body bore. fitv port is the lower of the two.
if it is stuck, you won’t be able to adjust idle correctly. if the fitv checks out, try adjusting idle AS PER PROCEDURE. if you can’t get idle to 500rpm with the iacv disconnected, with the air cleaner boot still removed, engine running, cover the throttle bore with your hand. if the engine does not stall you have a vac leak. the leak would have to be pretty big for it to effect idle past the point of the iacv’s correction capability. but still very possible. if the engine does stall, try and check your base timing AS PER PROCEDURE
For vacuum leaks try spraying small amounts of carb cleaner at various tubes/hoses on the intake and see if you get an idle surge from that.