: Please help with eratic idle!!!!!!!!!!



VIPERRACING
09-25-08, 07:47 PM
Hi guys, I have a 99 sts that has an eratic idle or hunting idle(up and down)after its warmed up and sitting in traffic. It doesnt do it when I turn on the a/c. Any help would be appreciated. Thanks, Tony.

Ranger
09-25-08, 08:01 PM
Sounds like a vacuum leak, but start with a good TB cleaning if you haven't done it recently.

VIPERRACING
09-26-08, 12:42 PM
Sounds like a vacuum leak, but start with a good TB cleaning if you haven't done it recently.

It only does it when im stuck in traffic. I turned on the a/c to see what would happen and it kept a steady rpm. I was thinking that it was the egr. Could it be the egr valve?

Submariner409
09-26-08, 02:16 PM
The fix is probably to: Do a good throttlebody cleaning. Do a good EGR valve cleaning. Pull the engine cover and do a thorough search for vacuum leaks.

If turning on the A/C temporarily cures the hunting, then the problem may be an erratic ISC system: the A/C ON command also increases idle speed slightly, so that function may either move the throttle butterfly or increase idle air just enough to "cure" the problem.