Idle stalling and hesitation at 2k

[johnyQ]

I know idle is talked about a lot, but after a few hours of searching I'm still a little lost.

I have an SSQV, fmic and exhaust. Car runs very strong and idles great when its cold (so its idling solid at 1200).

After it has warmed up the idle will get worse until it eventually stalls AND theres hesitation off boost at around 2k rpm.

What would be the most likely culprit in this case? Can I have a vacuum leak that would cause these issues but somehow the car still hits full boost?

[Nismo_Freak]

Sounds like an IACV problem, try to clean it out and inspect the area for leaks.

[johnyQ]

But the IACV is operating properly during warm up cycle (quick idle), so I'd be suprised if it was the cause for my bad idle once the engine has warmed up. But I could be not fully understanding its operation. Do you have good instructions for proper cleaning procedure of the IACV?

Does the o2 have anything to do with idle?

[rudee023]

On the first start up of the day my idle used to stumble really badly once it got warmed up. Turned out to be my O2 sensor. Not saying that's your problem but might want to make sure it's functioning properly. Strange too cause I didn't figure the O2 would affect idle. But I changed it out and sure enough.

[Nismo_Freak]

But the IACV is operating properly during warm up cycle (quick idle), so I'd be suprised if it was the cause for my bad idle once the engine has warmed up. But I could be not fully understanding its operation. Do you have good instructions for proper cleaning procedure of the IACV?

Does the o2 have anything to do with idle?

The IACV does not affect fast idle, the auxuillery control valve does.

[chillmieste]

My car does the same thing. the first 20 min im driving the idle will be fine and strong. but after that the idle gets a little jumpy, it sometimes even dies once i put the car in neutral. HOw do you check the iacv valve?

[johnyQ]

I replaced the o2 sensor, and cleaned the IACV the easy way (sprayed carb cleaner down it). Also checked hoses.

So far nothing has helped. My next step is probably take apart the IACV and clean it the proper way.

But is it possible the IACV effects my part throttle/off boost driving (stuttering and hesitation)??

and thanks nismo freak for bringing to my attention the auxiliary air control for quick idle.