I have a 2004 F-150 4x4 with the 5.4L and only 6500 miles. The truck idles rough and going up steep hills it seems the power curve bogs in the middle RPM range at WOT. The sound of the exhaust hints at me it is probably firing on all 8 cylinders, but it also hints that it is not normal. It just runs funny, except at WOT, but then I get the middle rpm bog.

I have tried an edge evolution with level 1,2, and 3... with the proper timing for the % of octane levels with the same results. I also disconnected the battery for at least 30 minutes when my battery went dead, and nothing changed.

Things that come to mind.
A Flat cam
Vacuum leak
a bad sensor or bad connection

Has anyone else experienced this? I can't believe this is happening with a low mile vehicle. The factory warranty is expired, but I still have my extended warranty.

Edit: My code reader shows no codes using the KOEO.

 

Have you changed the fuel filter? I it's an easy swap to make sure your getting good flow.
Good luck.

 

Can anyone else think of anything else that could cause this? What is the latest PCM update?