OK.This is my first Ford and so far not real happy. But I'm gonna chalk it up to it being used and 135000 miles. I got a 04 5.4L F150 Supercrew Lariat 4x4. I think its the tranny but between 1000-2000 Rpms under light acceleration it makes a humming sound like I'm hitting the rumble strip on the side of the road does fine if I get on it hard to medium. 2nd gear feels like it has no power and it shifts down so hard you can feel it in the Floorboard. Anybody got any ideas. I took it back to the dealer they said it was a dirty intake so they took it apart and cleaned it helped with fuel mileage but that's it. I want a direction to point them in before I go back.

 

I have the same exact truck with a few thousand miles less than you. I had similar symptoms that you have described. I suspected it was my tranny but was told otherwise. Needless to say, it eventually went down hard. I'm on my third tranny. The last one I got I had "built" to withstand some abuse. It has lasted longer than both the previous trannies combined while subjected to more extreme conditions. My setup is most likely more demanding than yours but you may want to drop the tranny pan at a minimum to see if there are any metal shavings and to look at the fluid color and interior.

 

Bad coils will also cause the symptoms you're describing. Next time you are somewhere that you can safely run it hard disengage the overdrive and gun it a few times. If your problem is ignition related you might hear a misfire or two and possibly a flashing or solid CEL which will direct you to cylinder with problem.