gap on plug closed inside combustion chamber


Asked by Dec 28, 2013 at 03:10 PM about the 2002 Pontiac Grand Prix GTP Coupe

Question type: Maintenance & Repair

On two separate occasions my car started missing because the electrode was sitting
on the firing pin. The second time it happened after a hard acceleration. It has 183000
on it. Previous owner installed a performance kit at 35000 with a smaller supercharger
pulley. I have put only 4000 miles on it in two years. Now lifters are ticking and maybe
a rod banging. I just found out i should have been using 91 octane. Is a piston hitting
the plug? Im assuming the engine is junk . Is a used engine with 100k on it worth

4 Answers


I would suspect someone put the wrong plugs in it . always use the factory recommended plug.

1 out of 1 people think this is helpful.

had NGK TR6, I put in Autolite5245 its happened with both type plugs. I would think that if plugs were too long all 6 of them would be hit


Because of using lower octane fuel severe denotation may have damaged the plugs. You should be using iridium spark plugs as well. They'll last 100,000 miles. That could also be the problem. HTH. -Jim

Paul Whitlock

Piston hitting the plug is likely what you have going on. Im with you likely a junk motor at this point. Id look for a shorter plug or try double washers to try to get a few more miles out it

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