I have a 2005 Mustang GT (5-speed). I just installed some JBA shortie headers on wed. I also just recently bought and installed a new JLT CAI with a custom tune, and with the custom tune.. the guys at american muscle plugged in the JBA headers to the SCT tuner. American Muscle is freakin awesome buy the way, fantastic customer service. Anyways, every since I installed the headers... my idle is very low. With the a/c off its at a 700-900rpm. 900 is ideal, and 700 is getting kind of low for my liking.. but when i turn my a/c on, it drops right below 500rpm sometimes... almost sounds like my car is about to die. That is not good for the motor at all. I'm in houston tx and you HAVE TO HAVE A/C here!

Before I change my idle in my tuner, has anyone had this problem? if so, how do you correct it without tuning it? Could it be the a/c clutch? The idle with a/c off is lower after header install also... The engine runs great when getting on it and you can tell difference with these headers... but just worried about the idle.

p.s. I also re-tuned it back to stock, then put the custom tune back it and it did not help.