The anti-fouler shields the spark plug's electrode and keeps it from fouling out. I am getting service engine soon light again, checked codes and it is only one now saying cylinder 4 is misfiring. Pulled the plug, and it was all dirty and corroded. Need to fix so I can smog it!! It was basically multiple misfires. Cleaned it with a wire brush, reset light by disconnecting the battery and that seemed to fix it. Your local auto parts store will have them.
One day it just started, and my step father checked the codes. I replaced all plugs, plug wires, rotor and cap. . No oil leaks from what I can tell. Try using a spark plug anti-fouler on cylinder 4. Basically the anti-fouler screws into the head then the spark plug screws into the anti- fouler.
Seemed to fix the issue. Js08016 answered 3 years ago Worn engine components, as mentioned above, can repeatedly foul out a spark plug on a single cylinder. . . .
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