Truck misfiring on all cylinders since around June 2007. Check engine light on some, off some. June 19 dealer said misfiring on all cylinders and they were stumped. They first guessed bad gasoline then said computer needed reconfiguring. Still misfiring when I left shop. On July 19 returned to dealer. They said it was a GM problem that GM was aware of...possibly crankshaft sensor and for me to come back in two weeks. On Aug 18 I took truck back to dealer after engine quit in a rolling turn in middle of intersection. Dealer replaced fuel pump and spark plugs and said they thought water was in fuel. Don't go back to same gas stations they said. I haven't. truck still was misfiring when I left. On 9-26 I went back to dealer. Truck engine shut off while I was doing 70mph down busy interstate. Made it to side of road, restarted and continued on my way. Dealer said it was computer loosing communications internally and had clogged fuel injectors. Left dealer and truck still misfiring. Drove it for a day or two and when friend who went to lunch with me wondered if we were going to make it back from lunch I decided to call dealer. Called dealer and was told it was a software problem and that GM is working on it. Groan! truck is almost out of warranty and I am wondering when next time engine will quit running and under what driving conditions. Thanks....roger dowdy

- Cottontown, TN, USA