Originally Posted by GXP303
Hello. New to the board. I own a 2008 Grand Prix GXP. I just replaced my exhaust system with a magnaflow catback system. I also replaced the cat with a high-flow cat. My engine light is turning on and I can no longer use my remote start feature. Should I put the stock cat back on? I Know these next comments sound crazy but it happened so here goes nothing. The other day I was parked off to the side of the road while on a phone call and abruptly It sounded and felt like someone hit my car. It jolted like it was hit. Any clue? Any help would be much appreciated. Thanks.
welcome! getting it tuned will take care of the CEL and was it the wind from cars passing you while u were sitting still maybe lol