The B2600i has fuel injection, not a carburetor. Mine had the same problem as you describe "after driving it for about 10 miles it loses power and you can only go about 40 mph. If you try to accelerate it spits and sputters and backfires." I found burn marks on my computer board. I removed the computer board (found behind a panel on the passenger side, by the passengers feet, just ahead of the door) and sent this board to a company in Florida that rebuilds them. Also, a short wire harness cable had to be replaced. This cable is located under the intake manifold and connects the main harness to the fuel injectors. Rebuild of the computer board plus a new harness cost me less than $400. I have tools and did the work myself. The truck has run fine since.
Tuesday, April 3rd, 2007 AT 7:45 PM