My buddy has an 04 GMC 4500 crewcab Rollback. A while ago we were at his shop and "modifying" my exhaust, and apparently it was contagious. He unbolted his stock system and made a 4' piece out of the 4" we used as a "kitty delete" He said it made a difference (and also very loud in the cab). He has been having all sorts of issues with this truck (even before he did this). Recently he decided to throw it on his scan tool (the local dealer he bought it from admitted they know nothing about Med. duty trucks and "shouldn't have sold this truck".) It was throwing 5 codes, one for the MAF performance, and the other four for EGR issues. The exhaust has been this way for about 5 months or so, (maybe longer). Recently, the truck has been running terrible. It starts, and when cold it sputters, falls on it's face, and when he tries to pull out, it won't move, stops in the middle of the road and just sits there. Couldn't get it to rev up, or anything, said it was smoking so bad when he was filling up the other night that his pumps dissappeared from view. Said he got worried it was on fire since it was smoking so much. Did the cat removal cause all this? The only attempt to identify the problem from the dealer was that they suspect a loose pin in the wiring harness :confused: Any help would be greatly appreciated.

I'd say he needs the reflash that most of us LLY owners have gotten.