I am having an idle issue. It started out random but does seem to be getting more frequent. Most of the time it idles smooth with no problems. But it goes thru times when it won't idle. It does not idle rough it just won't idle. I pull up to a stop a stop and it just dies, not spits or sputters, just dies. It always starts right and may idle fine for a while and then repeat. Someone has suggested cleaning the ICV but from what I could tell from reading posts the symptoms of a dirty/clogged ICV seem to be a rough idle. This seems to be more electrical, it either idles perfectly or not at all. I have done the idle relearn a couple of times and does not seem to help. I did one last night and took it for a test drive. It idle fine for most of the time and right as I pulling back into the house it did it again. Also, it does not ever throw a CEL. I do most repairs myself so I want to make sure I exhaust all options before I have to take to the dealer to diagnose. Thanks for any feedback...

 

Sounds a lot like a leak somewhere. Smoke or pressure test the intake system.

 

What gets me is the all or nothing aspect. It either idles beautifully or not at all. No spits or sputters, its as if you turned the key off. The first time it did it was on my way back to work from lunch and I had to nurse it at each stop light until I got there. I expected to have to do it on my way home but instead it idled fine again for weeks before it did it again. Which is part of the irritation, you have no idea when it is going to do it again. It may be tomorrow or it may be next month. I am wondering if I have a ICV going bad that at times just goes offline and thus no idle.

 

Mine does this too, and it only happens on the drive home from track days. Any other time and it is 100% fine.
I've replaced all four injectors, all four coils, the front o2 sensor, the alternator, adjusted / checked valves twice, capped the PCV, and dumped the front valve cover port to an open catch can along the way.

I'll data log next time it happens, I bet the STFT is way off.

 

The idle air control valve allows air into the intake manifold when the throttle is closed. It can surely cause the car to stall if it is not working correctly.

 

 

Aye

 

Thanks all, I will tackle it this weekend!!

 

One question, if after spitting the IAC the rotary shaft feels like it is sticking or not spinning smoothly, what do you recommend to fix? Should I just use the carb cleaner like what is used in the two chambers?