GM-GMC: Fuel system problem, throttle position sensor, range fuel

Question
I have a 2001 Chevrolet Silerado 1/2 tone, 6 cylender,my wife was driving the truck and it just died, initally I replaced the fuel filter. with no change. The truck is semi hard to start but when you drepress the throttle the engine dies. Could the throttle position sensor be the cause, or the gas pump. Any assistance would be greatly appriciated.

Answer
The fuel pump is a good posibility.  To be sure, check the fuel pressure at the port at the rear of the engine near the distributor to be sure.  Should be in the 60-65 psi range.  Fuel pump malfunctions are not uncommon on that vehicle, or any for that matter.  
Hope this helps