IndeedSS 
Some of the cars/trucks I've owned, where old high milage that used the plugs with a short life. You know the kind, backin the day, when some people would clean and reuse the plugs. The removal and reinstallation of plugs on those engine had to be multiple times greater that on my 55k mile 04. That said, how to you correct this issue? New ported heads? Yes? Good ,I need to go sell this to the wife.
Seriously though, I've been looking at these plugs and noticed the black powder residue is a lot thicker on the leading two CC threads, that all of the other plugs.
