Originally Posted By: eljefino
If that plug really is a bear maybe some slackjawed mechanic in the past replaced all 7 of the others and left this one alone.
Possible. IIRC, they are supposed to be replaced at 150,000Km (roughly 90,000 miles). I changed mine myself. Torqued them all and then six months later launched one. Also, another got loose by itself and had to be re-torqued (sounds like an exhaust leak). Been fine since (knock on wood).
That said, that coil failing is common due to what I mentioned earlier. So I would start with that. GHT does not have the tools or experience to change the plugs on this engine, I'm actually concerned about him changing the coil, particularly this one.