I have a 2000 F150 XL with 5.4L. It has 90,000 miles on it. I changed the plugs around 50,000 (15 years ago). I remember that it ran so much smoother after the plug change. It is not throwing any codes, but has a slightly rough idle that feels the same as before the last time I changed the plugs. My main concern is potentially stripping the threads when removing these old plugs. I can't remember how tight I made them since I was still a dumb kid back when I put them in. My concern is any thread damage could present itself after removal. Also possibility of being seized after so much time. Maybe a shot of liquid wrench a few days before I take them out? Maybe I just leave it alone and don't change them? Other than tie rods, nothing has gone wrong with this truck. Just basic maintenance for 22 years.

 

You won't strip them and they won't be seized. Proper torque is 28 ft/lb. In the very remote chance something does happen, the threads can be repaired without pulling the heads with a Timesert kit. Use only MOTORCRAFT plugs.

 

Yea, I will just go for it.

 

Good advice from GLC. I sprayed throttle body cleaner in the holes and let it soak an hour. Plugs came right out. Also, blow out the holes good before removing the plugs, a lot of crud falls down in there and could go in your engine. Don't use anti-seize on the threads, it will melt and foul your plugs. I torqued mine to 24 and they are holding nicely.