1999 Dodge Intrepid not sure

1999 Dodge Intrepid 95777 miles

I have a 1999 Dodge intrepid that seems to have a mind of its on. When I am driving on the interstate, the engine all of a sudden cuts off. I had it in the shop oce already and they replaced the idle sensor. I thought it had fixed the issue, but then it died again today on the interstate while I was giving it gas. The mechanic seems to think it is the fuel pump now but Im not sure. I dont want to have to keepreplacing parts that may not need to be fixed. The mechanic stated that before when the car was in the shop it had a full tank of gas in it so the gas was keeping the pump cool. Now that I have driven the car some and its down to a half of tank of gas, the pump is not staying cool and shutting the car off until it can cool off again. Does this sound right? Or could it be a different problem? Please Help[