I've got a 160K mile 2001 5.4L supercrew. recently I had a light throttle miss.

As luck would have it, while I was trying to figure out what was up, the intake cracked and became a more urgent problem.

While the stuff was off the top of the motor I changed the plugs, cleaned the original COPs and used dilectric grease, and reinstalled them.

That ennded my light throttle miss- NO problems ( actually flawless ) ran great for 3 months.

Now the problem is a little different, smooth idle in park or in gear, but a miss/skip gets worse as throttle increases, This time the motor does not have to be cruising at light throttle in overdrive to show up.

Going back to where I found the last problem, I pulled the easy to get to COPs and they look clean, no oil or coolant, grease still visable. No codes, this problem is evident at WOT not like the first problem.

Where would you look? COPs fuel or something else?

Thanks for your help.

 

Replace the cops. You can buy a complete set of 8 on Ebay for about 80 bucks. Search for DG508 and buy them from Global Automotive or Uneek Supply. Also change the fuel filter.

 

Yep, 80 bucks will get a new OEM set on your doorstep w/lifetime warranty.

What plugs did you use?

Over torquing the coils will shorten their life as well. Coils must be able to move freely on their bushings or they will fracture, suck in moisture and short the windings.

 

I kinda knew 160K miles was pushing it for original COPs, I'll get some DG508s and a fuel filter asap.

When I changed the plugs I used SP479s.

ALMOST put in autolite XP103s and was advised this would have been a mistake.

Thanks again for the direction, this site is a life saver.