I have a 03 Superduty. I bought it with 135000k miles. Price was unbeatable. Ford did a used car inspection but less than two weeks after the truck left the lot the #4 spark plug some how got loose and completly stripped the head. Now its in the shop and i am out money.

Is this a common problem for the 5.4 engine?

Also what other common problems does this year ford have so i know in advance?

 

Welcome to the forum

It happens, but not real often. It is usually caused by being incorrectly torqued. I guess they didn't inspect the plugs in the inspection, or if they did, they didn't tighten them properly.