Wow good luck with the thread-sert and hope it works for you. I just dodged a bullet on my 5.4 2v Utility Van today. I decided to change the plugs since I’ve got some time and thought I’ve been hearing a very faint exhaust leak. I changed The original plugs at 70,000 miles and I only have 122,000 miles now. But knowing how they are prone to loosen up I thought I’d rather be safe than sorry with 52,000 miles on this set instead of waiting until 70,000 miles. I’m glad I did! #2 cylinder boot was burnt and the plug was loose enough for me to spin it out with my fingers. It’s not real easy putting plugs in the E series vans with these big modular engines but well worth not waiting until the scheduled 100,000 mile plug change. It’s too risky in my opinion. I installed the last set and I am known for over tightening and snapping things off from putting Hercules torque on everything, and I still had one loosen up. I also remember when I changed the originals at 70,000 miles I had a couple plugs that were barely snug at best. Check out the set on the left.