I have an 06 gt with a bbk CAI, diablo tuner running the 93 performance tune w/ MAF adjusted up 10 to compensate for the CAI, Flowmaster axle back, 3.73 gears, and now Granatelli coil overs. I installed the Coil overs and and they work great at wide open throttle but at low RPM's it studders, hesitates. Usually happens in 4th or 5th gear at 1500 rpms. Should i look into getting a custom tune or is there something i can adjust using the diablo tuner to get rid of the hesitation?

 

Aftermarket COPS have been known to be real headaches. Return your COPS to stock and see if the problem is gone. I'll put money down that's the issue.

A good custom tune would help performance but I doubt the tune is the problem.

 

I bought these from a buddy that sold his car and used them for 10k miles. He never had this issue though he did have a custom tune off a dyno. I'd rather not go back to stock COPS since it actually feels alot stronger at WOT.

 

it could be your imagination. COPS don't provide much of a power gain unless you're FI.