when cranking my car it has a really bad miss. the code reads random/multiple cylinder misfire. I just replaced the plugs and wires. I also tested the coil packs to check the firing and all produced a big blue spark like they should. what is causing this to occur?
hard miss on 2004 Pontiac Grand Prix GTP
Did this start after you installed the plugs and wires? If so there may be a bad spark plug or you may have crossed the wires. Recheck your work.