Contour Enthusiasts Group Archives Forums General Troubleshooting Sparkplugs Un-Screwing themselves?

I have had plugs not seat because of the welding of the hook electrode interfering with the threads. You could have stripped threads, I hope not! If you have a Duratec, try APP764 Autolite plugs. Thread in by hand on socket extension, seat firmly but not brutally with short wrench.