Pandaman

I searched the forums here and found quite a few results on idling problems linked to IAC, but there wasn't anything that matched my situation similarly enough to where I felt comfortable, so I figured I'd ask again...

My car on the first start everyday is fine, and as long as (I've noticed this is a pattern over the course of 2 months) I don't start it again for another 1-2+ hours, subsequent starts are fine. The problem occurs when subsequent starts after the first are less 30 minutes after, in which half the time, it'll start but go from 1 rpm when it starts straight down to 100 or 150 RPM w/in a second and when I put it in reverse engine will essentially stop. I usually turn it off then turn it back on and its ok, or i turn it back on and give it some gas, and that alleviates the issue...

Now that the weather has warmed up considerably, the problem is happening almost everyday on subsequent starts that are within 30 minutes of the first start (vs once or twice a week), and today, it got even worse. I stopped at NAPA Auto Parts and came back out in 10 minutes and my car wouldn't start on the first 3 tries, 2 of which I gave it some gas. Finally on the fourth it started (w/ gas). Happened again a few minutes later when I stopped to get gas- took 3-4 tries to get it to turn on, but ran great after that.

My mechanic thinks its an IACV problem, but said he would hook it up to the machine to be sure. Does anyone think it could be something else, or does the IACV seem to be the culprit? I read about some ppl referencing spark plugs, ECU, TB, MAF. It's frustrating b/c it may be affecting my mpg (which less than what it should be giving) b/c of the richer mixture involved to get it to function properly. THank you for your input/responses, I really do appreciate it.

**would also like to add that sometimes even after its been sitting for an hour or two, the idling still acts up occasionally

PFB

Start by checking for any stored or pending trouble codes in memory. Autozone as well as Advanced Auto Parts will check it for free.

MikeLex

Besides cleaning the IACV, carefully check the fuel pressure regulator for leaks. You see no problem on cold (or almost cold) starts because the ECM tells the injectors to add an extra amount of fuel whenever the coolant temp is lower than normal.

Pandaman

Thanks for your responses...

This might be a dumb question, but how would I check the fuel pressure regulator for leaks?

MikeLex

Pull the vacuum hose from the FPR with the engine running (or key on, engine off) and look for fuel leaking out of the nipple. There should be none, otherwise the FPR needs to be replaced (BTW, it's plug'n'play).

Pandaman

No leaks. I think the best thing for me to do is get it plugged up to the machine and check for codes. Thanks Mike.