rolex11

Did you ever figure out what your idle issue was caused by?

I know this thread is over a year old, but I have exactly going on with my car as what you were experiencing. I did most of what you did, cleaning things, replacing things, oil cap removal and so forth....

I'm leaning towards a failing AOS at this point...

interested to see what your fix was if that's the case...

jrp3000

Knocking on wood as I type this, but one day it just quit doing it. I have put another 8000 miles on the car with no issues. Only advice I have for you is to order parts on Amazon, if they don't fix your problem, you can take them off and send them back for a full refund.

rolex11

Hey, thanks.

Your entire story reads just as mine to the T.

Replaced the idle control valve, throttle position sensor, cleaned throttle body. Smoke tested for vacuum leaks, etc. Nothing seems to fix it.

When I remove the oil cap there is no idle change which I'm told is good. No excessive vacuum when I remove it which I'm told is good. Both indicate AOS is ok. No smoke from tail pipes.

Some times my idle runs high and other times I get the hunting idle bouncing from around 500 & 800 rpm. Both can occur when engine hot or cold. And to boot, it can idle great for weeks then out of the blue idle bad at a stop light, then next light it's fine.

Only thing I have not done is replace the oil filler tube cap. It seems tight but the rubber gasket is chewed up a bit but looks like it should seal properly.

When I do notice the idle problem and pull over and take off the oil filler cap and then replace it the idle corrects.

Thanks for updating me. I put in all the details in case someone else wants to chime in with their thoughts.

Gulliver

Mine with similar symptoms turned out to be intake boots, my car is higher mileage, 125k

996-110-686-50 (x2)
996-110-685-52 (x2)

rolex11

Just in case it winds up mine are bad.

What is involved replacing those, cost, does engine need dropping?

Thanks

rolex11

Just changed my oil tonight.

I had noticed my oil level was high, about 2mm over the little dot on the dip stick.

I was thinking maybe my idle problems were related to too much oil, is this possible or not?

Took it out for a good 80-90 miles drive with many stops, and it never once idled bad, in fact it seemed to idle spot on. It's been idling bad at least 2 or 3 times every time I've driven it for the last few months or longer.

Maybe I'm on to something here.

Maybe that's why yours corrected itself jrp3000, maybe you changed the oil and that's when yours stopped.