feul pump going crazy

i went to my brothers house monday just a few miles down the road and when i went to leave my truck wouldnt start well after checkin everthing we figured out the feul pump wsnt runnin so i left the truck there i went over to work on it today cuz a guy at the parts store said u can hit the tank a few times and if will usually work for just a lil while so i go over there and before i do anything my bro takes the key and trys to start it and it fires up and runs greatand i was like is my feul pump going bad or is it just playin ricks on me