whats wrong with my idle?

[92bluetalontsi]

My 92 eagle talon tsi runs great but after I drive it for a while and then come to a stop and put it in nuetral the idle gets really bad going from like 750 rpms to 1200 rpms. wondering if this is common? and what i can do to fix it because it gets really annoying, and i get alot of bad comments about the idle.

 

[CurtTSI]

It's a common problem, called idle surge. Usually caused by one of three things.

1. Bad ISC (Idle Speed Control) servo.
2. Vacuum leak
3. Dirty throttle body.