01yellercobra
Active Member
- Joined
- Feb 23, 2018
- Messages
- 628
- Reaction score
- 193
On my son's 99 GT when he turns on the A/C or defroster the RPM will jump up to about 1500rpm. It does it with or without a tune in it. My initial thought is the IAC. But I've never had them cause a jump in RPM. Usually they go the other way in my experience. What do you guys think?