the 2002 Chevrolet Trailblazer has the 4.2 motor. number 5 cylinder has a miss. plugs have about 50k on them. seems to get worse under a load.
Answers from the Automotive Experts
Jim,
If you have replaced your spark plugs, and wires, and still have a misfire on #5 you can switch out the coil pack with its neighboring coil pack. If your miss fire moves to the replaced cylinder, then replace that one coil pack.