Wierd Idle?

[slantedpillow]

When i'm idling at a stop light my P5 shakes and idles just above 0 all the way to 500. What is going on and how do i stop this?

 

[SilverSavP5]

Do you have a CEL. I do and I had the same problem, broken o2 sensor. My mechanic said to put premium in it. I've been doing that and it's been fixed until I can get a new sensor. Hope that helps.

 

[slantedpillow]

Thanks! i actually just had a PO421. So i just wiggled the pre cat O2 sensor and boom. Fixed! But i will try the premium. Thank you!

 

[Rusty]

If the problem still persists, check if you have the stock air duct and make sure it isn't dry-rotted and cracked between the accordion shaped ridges. Lots of them are doing this lately. I just replaced mine a few weeks ago. Swirling air comes in after the MAF sensor and confuses everything.

EDIT: Oops, I hadn't refreshed in a while. Didn't see the last replies before I posted.

 

[sethro_GT]

+1 on the cracked intake tube, mine is cracking and now my idle is super high when cold and jerky when letting off the trottle.

 

[Rusty]

+1 on the cracked intake tube, mine is cracking and now my idle is super high when cold and jerky when letting off the trottle.

Yeah, it can get screwy. The MAF tells it one thing about the intake air, and then the actual air at the throttle body is different.