I need some help, I just installed a Magnaflow axle-back kit, and a K & N cold air in my camaro. Engine light came on now 3 weeks later and I did an OnStar diagnostic test and they informed me that there is a malfunction with my Engine Fuel Control System? Could this be cause by the CAI and Magnaflows that I installed and do those parts void my warranty??? Please help!!!!!

 

Those mods should not affect the EFCS.... That is electrical. Take it to the dealer to diagnose as soon as you have time.

 

I doubt that the cat back is causing the problem, but there is a good chance the KN set up may. New cars are calibrated to work in a very narrow range, and will complain if things aren't just right. You should have the computer scanned so you know exactly what it is complaining about. I've seen several cars with LS engines complain about lean mixture several weeks after a K&N intake was installed. Probably due to the air not hitting sensors just right.