2003 4.6 starts and drives fine, at normal driving, if you give it a lot of gas it will not respond,not sputter or fall on its face just won't rev up like it's getting gas, I'm thinking tos only thing I can think of any help

 

I know this is a super old thread, but to anyone reading, there are numerous issues.

I would check fuel pressure. First replace the fuel filter. Then monitor fuel pressure at idle, and when revving the truck.
If no issues exist, move on to spark. Replace the plugs. Coils are not common failure Items on the 2v mod motors.

If spark and fuel are good, air is at that is left.