Hey Scotty this shows up on the scanner for my 02 blazer. Most all sensors have been replaced, plugs are new and wires are a year old and distributor is new. I didnt see any arking from wires but i can see the electrcity flowing through them at night. What could cause the misfires and do you think catalytic converter is needing replacing? 174,000 miles 4.3 vortec

you should see nothing at night, change the wires first and pray it's not the vortec injection system plastic parts all cracking and breaking down