New member here, lurking for a long long while.
But n

Everytime you dont ease into throttle or its a cold start, this happens....why?
ever one to be outdone, my ol 2005 5.4 is chock full of surprises, can someone here please tell me why I always throw cel for cyl 7 misfire and find my plug looking like it's been decapitated? I been on my rig for a while, and yeah she ticks and sounds like a silenced diesel but I've never seen anything like this, let alone it happening repeatedly like every time you don't ease into the throttle.
any help would be appreciated fellas, thanks.

 

You are getting blowby . Gases are coming up the threads on a lose plug . That makes a cutting torch out of that area . Your strap is missing due to that burning , carbon around snout is white hot, oxygen being sucked in on intake stroke, hot gases being pushed up on compression stroke .
It ruins plug and boots . Torque value is now 25 to 28 foot pounds ,use a torque wrench -this is a common event .

 

Thanks for the comprehensive breakdown.
I replaced plug,boot/coil, torqued properly, now wait and see what happens.. this has happened like 5 times every time it's #7, im starting to wonder if the minimal threads are wearing down. These plugs should go 60k atleast, my rig has 126k or so on it and has had 3 full sets of plugs, coils/boots, and #7 is on like it's 7th or 8th plug already, I wonder if they been changed too many times already for those jacked 3 threads they give us? Thanks again

 

Well, if it's happened 5 times and is always this same #7 hole, I'd be investigating a thread insert repair. There are some made that are likely even better than OEM even. Steel plug threads in an aluminum head, only takes one time with a loose plug to eat threads out. Being #7 isn't quite as hard to reach as #8, but it's close. As far as I know, the 5.4 three valve heads have more than just three threads. They pretty much use all the threads you see on the plug. If there ever was a loose plug, there's a chance your head has a notch cut from flame travel and steel threads wiggling with every firing will eat away at threads.

My #8 fought me, then the threaded part of the plug came out but left the porcelain in the hole, this was the Porcelain Puller I had overnighted to me to pull it. It is a good picture though, shows threads.




My '01 Mercury with 4.6 two valve has just three threads, I changed it's plugs once back in mid 2006 or 07, torqued those gently at 14 ftlbs. I was well aware that it had just 3 full thread heads.
My 5.4-3V in my '07 truck was torqued at 25-26 ftlbs in 2019.

 

If its the same plug hole every time then it needs an insert . The best there is is time sert its expensive with all the tools involved . Best to take it to someone who has all the stuff to do it right. Do not use Heli coils they will fail . Someone has already screwed this plug hole up . If it was Heli coiled or inserted - cheaply its going to be a head repair job . May have been cross threaded in the past .
Its camera time to see what's in there . Some guys will not take the time to let the thread lock take hold on a good insert = no patience at all . Maybe Biden worked on it .