Firstly, absolutely great forum for the F150. Have been able to find out just about anything and quite a few things not aware of.
I joined quite while ago and used the forum as a reference, but I don't think I ever actually posted, at least I can't remember (sucks getting old).
Anyway, I've owned an '03 SC FX4 5.4L since new, about 260K on it now. Was my daily driver for many years, now a retired weekend job truck.
Never really a major problem with it (I know this is a major jinx) and the best vehicle I've ever owned.
Had the plugs done at the recommended intervals and appeared to avoid that whole issue, just had an exhaust manifold replaced, and other than the rear axle seals around 80K, other things were normal wear (u-joints, front end parts, alternator, battery, brakes, tires. Still on the original muffler and exhaust.
However, while mechanically it's been excellent the Northeast winters have taken their toll on the body. Rusted out rockers, bottom of door panels and bed supports.
I'll just keep using it for hauling and some light plowing till it passes.
Again, great site and thanks for everyone posting all the valuable info.

 

Welcome! Good to have you joining in.

 

Welcome to the site... Enjoy the ride and keep coming back...