I just bought a 2001 f150 w/4.6l engine that had blown out a plug.The owner said it was a common problem but I only found one other person with this problem on your site. Have you heard of this being a problem.

A ford is a problem from the day it is built, On that mechanic friendly model the plugs tend to seize down in the 6 inch well and break when trying to remove them .Then you could call it blown out ,Theirs no porcelain or top half of the plug.,Maybe I'm in the twilight zone cuz theirs several cases I've seen the last few yrs.

Supposedly ford didn't put enough threads in the heads causing compression to actually blow the plug right out of the head. The previous owner tried to put in a helicoil and that's when it all went bad.

That's a all to common a problem. The engine has to be DEAD COLD and pray the last time they were changed someone put anti seize on the threads. But it doesn't sound like that was the case with yours. I've read that IF you can get the plugs 1 -or 2 turns lose, spray some penetrating oil down the spark plug hole, wait a half-hour then they might come out. I think you're going to have to replace the head. I hope you got a good deal.

the thread area in minimal fired compression is maybe several hundred pounds, I think the removal and reinstalling without a lube can booger the threads setting you up for disaster after a while . believe it or not I once had a seized plug in a dodge four banger and needed changed real bad. knowing it would ruin the head in an un-tapping area the new replacement I brushed the now gone threads and j.b. weld the plug to experiment. it worked! as long as I know its still running .ran it several thousand miles before sold