Truck stalls when gas is pressed it stalls

One possible cause for this would be is the mass air flow sensor which is located on the air filter box. I recently paid around $90 dollars for one. I don't know if this part can be checked or not.

Another likely cause is the fuel pump. I had this problem recently and this was the cause. The pump is mounted in the top of the fuel tank. You can have someone check the fuel pressure coming to the fuel rails on top of the engine to verify that this is the problem. The easiest way to change the pump is to remove the bed, giving easy access to the pump. These pumps are still rather expensive, in the range of $200 dollars new.