My 97 150 has 205,000 miles on it and has picked up a slow speed miss, I can step on it and it will not miss all the way to wide open shift, no tach.
It had the plugs and wires changed at 100K, I guess it's about time for another set, I didn't change them the first time.
I am going with motorcraft plugs, my question is how hard is it to change these? It looks like a tough job.

 

Its not that hard on the 4.6 easier then the 5.4 Start with a set of plugs then if it still runs bad pick up the wires.

 

its rather simple and straight forward..

 

do yourself a favor and change the wires while u're at it. just change 1 wire and plug at a time, and make sure u put the wires back into plastic holders that they come out of. when u buy the plugs, go ahead and get a long extension for your plug wrench. it needs to be about 8 or 10 inches. It'll make things so much easier.

also, if your wires are really bad, crank the truck at night and look for blue arching light shooting off the plug wires... the 2 back plugs are the worse, but they're not all that bad.