The idle in my car after it warms up goes up about 200 rpm then goes back down and then back up and so forth and so forth any ideas on what could be causing this? It irratating, could it be the IAC sensor? Just wanted to get an idea before I starting taking things apart. Thanks guys.

 

It can be the IAC maybe, but check all the vaccum lines also, maybe there is a funky leak somewhere and that might be causing it too. To tell you the truth, I don't know, but check it if you have time.

 

Thanks....anyone else?

 

double check all of your vaccuum lines first. ( or just replace em, their like $5 for all the lining you will need ). then if that doesn't work, unbolt your IAC from the back of your intake manifold, when it is out check the o-rings for wear, if they are ok, just put some grease on them. then check the filters, ( on the backside i belive ) ...try sprayin it w/ carb cleaner and leavin it out for a little bit, then rinse, clean, dry, and re-install. You could have a vaccuum leak ie, throttle body, intake manifold, but those things just don't happen without you messing with them. my friend has the same problem after he shot a 75 shot. good luck man. later.

 

vacum leak...check the lines

 

How many miles on the car? I have heard impending timing belt failure could cause idle "wobbling."

Rainmaker