Went to a GM dealership on Friday to get my trucks surging and smoking problem figured out. The truck did this every once in a while before I put the six gun chip, but after the chip it did it at every stoplight. The service manager said with the chip installed the number 6 injector dropped to about a third of the pressure it should have. With the chip unhooked as far as they could tell the truck ran fine, but he said that they could only tell for sure if there was a problem with the injector if I returned my 4 inch exhaust back to stock. They won't touch it for warranty work until the chip and exhaust are either.

Remove the six gun and take it to another dealer. The exhaust isn't your problem. The dealer is just kissing GM's Arse. Of course you will have to duplicate the problem without the chip.

What would your exhaust have ANYTHING to do with an injector?

Never take a vehicle into a dealer if you have modifications if you can avoid it.

You wouldn't believe some of the crazy stuff I've heard! Some:

"You apparently are driving vehicle outside it's design parameters" - Clutch sticking to floor on 2000 Camaro, another dealer fixed it.

"Your warranty is void because you have Nitto brand tires on the car. This indicates you are racing." - Told to a good friend who never races, but put "racing style" tires on.

Etc, etc.

Some dealers will do anything to avoid doing warranty work. And then when they do it, they will take shortcuts or write up stuff they didn't do. You need to find another dealer, as it sounds you've found a "bad" one.

PS - You can replace your muffler and muffler pipe with any brand you want and maintain the rest of your warranty. Mufflers are replaceable components. They know that. The cat? They CAN refuse to work on a car/truck that has had emissions equipment disabled.

I agree with all of you. I had a very slim hope that they might fix it without giving me all of their B.S. about the aftermarket add-ons. looks like I was wrong. What made matters worse was that the area rep just happened to be there. He was the one screwing with the chip and other things. I was just hoping for a reflash, but they told me after calling tech support etc. there was nothing like that available for my truck.