my truck idles fine but as soon as I give it gas it dies

When was the last time the oil was changed? Good oil is so critical to proper operation of this motor. I recommend Motorcraft 15w/40. The things that this motor needs is high oil pressure and good fuel delivery. The oil pressure required to run this motor is very high, so low oil level is not good,(takes 12 quarts at oil change) also aeration of the oil can hinder performance. Idle the motor for a while,shut it off then check the oil level, if you see any bubbles in the oil on the dipstick, the oil is no good. If you can get a sample of the fuel after the fuel filter and put that sample in a glass jar, see what the fuel looks like, if it is gray or black, then motor oil is leaking from the high pressure oil system passed the injector "o" rings and getting into the high pressure fuel system. If this vehicle has a rectangular shaped air filter, check that, they were notorious for plugging up. Oval shaped air filters were not as much a concern. These are the first things I would check, if those items are okay, then you need to have the engine management system scanned for trouble codes. Good luck.

Maybe the TPS, (Throttle Positioning Switch) I had to buy the whole acelerator pedal and bracket assembly to get the little switch that is in the assembly, it talks to the computer and provides fuel to burn when the pedal is depressed. Very easy to install as it came out of the box... 1 electrical plug and I think it has like 4 screws to drop out the old & install the new. Please let me know if I was on the right page with you Thanks- Nicky P. in connecticut.

Have you checked the MAF sensor? I had a 1999 2500 that had this happening. Would Idle fine and die off when I go to give it gas. Replaced pretty much everything from spark plugs to wires to fuel pump and filter. Nothing worked until I replaced the MAF sensor!