1998 Chevrolet Silverado • 170,000 miles

My truck, while pulling lawn equipment, started misfiring. I took it to the mechanic and I had him replace the wires, plugs, cap, and upon further inspection I had him put in a set of spider injectors (it was a used set, but a complete set form a truck with 80,000 mi.). It still misfires and the exhaust smells like fuel. I took it back to the mechanic, we agreed that he would continue working on it, and he took out 3 spark plugs on the drivers side - 2nd, 3rd, and 4th plugs on the driver side ( the 4th being the 7th cylinder) All 3 are black with carbon. I think it may now be a timing or firing issue
October 23, 2012.

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