Well this issue first started at WOT a while ago but I thought it was related to my motor swap and lack of proper tune. Fuel PSI at idle was good. The power would cut in and out at WOT. At one point it was cutting out real bad cruising on the freeway at part throttle. It did that for 2 days and was fine for 10k more miles.
WELL, after changing tuning methods it was still cutting out so I did some googling. I saw someone with a similar problem that said their fuel PSI was fine at idle but dropped way down at WOT. I figured with 170k on the clock this had to be my problem. I bought a new fuel pump and hanger assembly for $2 more than the cost of the pump alone. The problem is GONE! It pulls steady now at WOT.
On a side note: Do yourself a favor and if you are dropping the tank make sure you get a new filler neck grommet seal. Mine was trashed and none of the big 3 parts stores carried it - special order only (Dorman brand or OEM Ford). I had to throw it back together to drive her to work and the next day the seal tore and gas was freely flowing out