This has been an issue I have lived with since I purchased the car and was stock because I have zero codes and it is mainly a nuisance. It never happens on cold start or cold weather. Seems to be when the car is warmed up. The car starts and idles fine. But when the A/C kicks in high initially it bogs the engine down and the idle drops. If I attempt to put into gear and drive the car sometimes stalls. Does anyone else have this issue??

 

Have you checked for vacuum leaks?

 

No, but all other aspects of idle are fine. Why would a vacuum leak only rear it's head when warm and A/C kicks on?? Not saying your theory is wrong, just that I don't understand our vacuum system as pertains to the particular start circumstances that cause this.

 

Def sounds like a vac leak as when the AC kicks on and loads it up it wants to stumble.

 

I've had vac leaks appear only when warm. I figured it was due to the difference in expansion of the metal and rubber pieces where the leak was.
Could your problem be caused by an ac compressor starting to seize, slowing down your idle?

 

I have only noticed a vacuum leak when warm. Probably wrong, but I thought the ecu controlled idle one way prior to the coolant reaching a certain temperature, and differently afterwards, hence why vacuum leaks only show up when warm.

 

If you are running a MAF check that.

 

Good thoughts and input on the vacuum leak.

I did replace MAF after purchasing my car for this issue and it didn't make a difference. I just ignored it from there.

 

I've been following your musings here for years. so, by now, that maf could well be fried. i recently replaced mine and it cured what i was sure was a vac leak. but $180 is my upper limit dollar threshold for the "throw-a-part" game and this time? i won the prize

 

True. But one would think the new MAF when I first purchased would have solved the issues for a while until it failed again.

Now I need to find a good vacuum leak checking DIY procedure for our cars.

 

i agree, and somehow missed that you had the issue still even after swapping with a new one. there's another thread going with a "hot start" issue. i wonder if you guys have similar issues? if mine cranked 4 or 5 times pre start, i'd think my fp was failing!

i'd also like to see a comprehensive 'list" of any/all vac leak testing procedure. but is it not as simple as checking every hose and line of the intake system from the ic''s all the way to the plenum and incl the check valves?

 

Other cars usually suggest smoke testing.

 

for ours, pressure testing is enough. or, has been for me.

 

Where do you tie in? And do you use a mityvac?

 

from the turbos. its a homemade home depot thing just hooked to the compressor. I'm sure you've seen em..its not mine. its my pal that wrenches on the car on stuff we can do in his garage.