iRub1Out

My 04' with the 5.4 has a horrible miss or stutter in the 1500-1800 RPM range only when it's under a load. Going up a hill, or maintaining speed on a flat stretch, it always acts up around 50-70mph if the TC doesn't unlock allowing the RPM to come up. It hasn't thrown a code, dealer has gone into "mode 6" or whatever, and still found nothing. Edge (now sold) said COP on cyl 2 was bad, replaced it, problem persists.

I have tried replacing COP's, different fuel, checked for vac leaks, reset the PCM... Many many possible fixes, but nothing has shown any improvement. If anyone has any ideas I'm all ears.

Terrible One

Maybe your spark plugs? Mine did the same, once i changed the plugs it fixed the problem

iRub1Out

Thanks for the reply, but I forgot to mention in the OP that I had done that also. About 5-8K miles ago they were all replaced. I'm not saying that isn't it, because I'm sure that's possible. Any other thoughts?

kevhead75

What kind of plugs did you use?

ranger42883

My truck is doing just about the same thing...plmk if you find a solution. I am in the process of having my exhaust components looked at

goldteam

if u have straight pipes try getting an intake or the gotts mod, mine did the same after i had straight pipes put on and did the goots mod and runs smooth now

iRub1Out

I am pretty sure we put motorcraft plugs back in it. The dealer did it, so I'd imagine that's what was used.