No wonder I had a misfire in #3! Wonder what causes this? Bad boot? Bad insulator? Cracked insulator? Maybe water got into the boot? Maybe there was too much of the silicone grease used in the boot where it pushes onto the plug connector and it ran down? If the grease is even conductive, but silicone, I don’t know?

At any rate, just thought I’d post this. At least now after replacing the plugs & wires, the misfire is gone and the check engine light is off too, YEAH!


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Are you sure the grease you were using is di-electric and not conductive instead? Di-electric grease is non-conductive, so if you are using di-electric grease, it will not be the cause of arcing, and should prevent water from getting under your boot. Clean the burn marks off the ceramic, and see if the ceramic is cracked at that location.

 

Hello,
Since I posted I did inspect it a little better and rub some of the carbon off. The insulator was cracked! I just bought the truck, so I have no idea what was done (or not done) to it before… that’s why I am going through it and bringing all of the maintenance up to date. Something went terribly wrong with this plug though, that’s for sure….
thanks

 

It could have been either dropped or installed incorrectly not using spark plug socket.

 

I have one looks just like it (except it was an AC plug in a Chevy). Plug was 1 month old, I installed it, no dropping, no overtorque.
I never figured it out. Has run good ever since.

 

Yeah, I have no idea, since I just got the truck but something sure went wrong? I made sure when I replaced them that I torqued them to the required 15 ft-lb’s. and used anti seize on the threads too... Hopefully it was a fluke? bad plug, bad installer, dropped etc.? and Not from an overheating cylinder or something else on the truck? Looks like it was just the plug that was bad / broken... fingers crossed...