how to change spark plugs
There are no plug wires on a 2003 5.4L. There are coil packs on top of the plugs though. When changing the plug be sure and use anti- seize on the plug threads as they can seize up in the aluminum head.
And do not exceed the torque in inch pounds as recommended by Ford when installing the new plugs. It's isn't much, maybe 160 inch pounds, if that. Stripping out the threads on a head gets expensive to repair, and a big pain in the butt.
Search Ford F-150 Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Ford F-150 Experts