yeah sk8terdude, you need to get ahold of someone that can "tune" the car (ie. with hpt or dhp) 01+ cars have cat diagnostic checks that are ran. without a rear o2, fueling issues, and troublesome ones at that can occur with deleting it.

here, read this whole thread, i know its alot but it will give you a better understanding of the "diagnostic" tests that are ran by the pcm..
http://www.grandprixforums.net/remov...know-7092.html