I have an 06 F150 2wd with the 5.4. Today on my way home I had to cross traffic while getting on the highway and had to get on it a bit. When I gave it the gas the truck down shifted then just fell on it's face until I let off the gas a little then it sped up like normal. It normally runs great but I don't get on it much. I just don't see why It runs great until I try to get a move on. Any help would be great.
Thanks

 

It could be a fuel pressure problem. Maybe a dirty fuel filter or the fuel pump could be starting to fail.

 

my truck does the same thing, did you get it fixed?

 

My 07 was doing the same thing sporadically until I change the spark plugs out. No problems so far. Good luck changing the plugs though, what a nightmare they can be.