Originally Posted by barriosman

Rule of thumb (from what I have learned on this forum) is to at least replace the boots too. I replaced the coil pack, but some just do the boots. Over time, the boots deform to the shape of the plug.

Originally Posted by Oilfield_Trash1953

Kinda dealt with the same thing. But I'm in a lot worse shape. Had plugs and everything changed 2 months ago with 111k miles while I was at work in ND. Come back home truck runs great. Came home this time and it's missing again. Took it to my mechanic friend and used his computer and it said cylinder one misfire. Changed coil again and still misfiring. Took coil off and noticed the plug was loose. 2 turns by hand and plug came out. Now dealing with a hole in the piston. Guy won't stand behind his work. Plug doesn't look 2 months old to me.

Originally Posted by MGD

Yep.

OP - did you also use fresh dielectric grease in the boots? And apply it properly, like this:

https://www.f150forum.com/f38/recomm...2/#post3272459

good luck

MGD

Originally Posted by barriosman

+1 I would default to what MGD says. He has a hell of a lot more experience working on these rigs than me. I am a mechanic of the shade tree variety.