1999 Chrysler Intrepid Fuel system

My car is a 2.7 liter. It will start and drive different distances each time it does actually start. Sometimes I can hear the fuel pump activate when I turn the key, then it will start. Then other times I cant hear it activate then it obviously doesnt start. It never makes it very far even when it does start. Now in obvious thought a guy would think it was simply the fuel pump?But ive had people tell me when a pump dies its simply done and wont continue on teasing you by working sometimes. It seems to stop running after the car is warmed up and driving a little while. Although sometimes after it sits for along time, it still wont start.A friend suggested it was the camshaft sensor.I bought a new one and put it in. Same thing happened. Then someone suggested it could be the crankshaft sensor?Im done doing things to just spend money with no results. Could it be the fuel pump?And would it still work for short distances then quit again?