Thread: Random misfire

Just replaced the the plugs and wires and my miss went away for a couple days and now it's missing again. I'm getting random misfire and knock sensor code on the scanner. What could cause random misfire code. I noticed one of the prongs on the coil pack was rusted when I changed the wires I cleaned than up and still have the same results. Seems to run fine under idle but runs like crap at wot. I'm gonna remove the plug wire heat shields and see what that does. I'm starting to think it may be injectors.

Autolite 606's

Could a vacuum leak cause it to misfire? The vacuum hose around the supercharged was brittle and broke

yes it could, I would suggest replacing all of your vacuum lines. its only about 4 bucks for the lines and 2 for the vacuum-T's

I'd say its likely a coil pack issue or a ICM problem.

Vacum leaks are common on old high mile engines and definitely cause misfires.

Yeah I replaced some vacuume lines today and it seems to have fixed it. I got a fuel filter while I was at it. I figured since the plugs and was original the fuel filter has probly never been changed. It's amazing how people won't take care of there ****.