[Jeff Lee]

Somebody was just asking about this problem. I just had the plugs replaced about 15,000 - 20,000 miles ago.
I could tell yesterday something was wrong as it developed a mis.
Today the check engine came on. Went to the same shop and it coded bad #7 coil. Then they noticed the spark plug was loose. Since it would not tighten, it's stripped. That's all I know so far, have to wait until Monday now.
I know the "help" section at Checker & AutoZone sells an "on head heli-coil" insert for this. I guess the theory is any particles will be blown out the exhaust. Being that it is #7 on this Expedition, I can't imagine it's easy to vacuum it out.
And of course I can't imagine the labor in pulling the head off and doing it the right way.
Any ideas?
And I've had the famous tappet noise for quite awhile also. Is that most likely in the head assembly or cam adjuster. No fault codes and TSM's seem to indicate this is normal.
Truck is too nice to get rid of (and I just spent $1500 on all new air-ride parts) and a new vehicle is just not in the budget.
I even looked at the 2011 GT 5.0L at $6999 retail and boy, that sure would be cool and cost effective but I can't imagine it's an easy swap. Or is it?
Thanks for the input!