When you change the fuel pump you'll have to be sure the pump rod stays up. There is a bolt on the front of the block around the corner from the pump. It is short and dose nothing but fill the hole. It should be removed and put a longer one in to hold the rod. After changing the pump remove the long bolt and reinstall the short one... If you have never done this type of repair I would recomend getting a book that covers your truck they cost about $30. and can be purchased at most parts stores. Good luck it realy isn't hard.Just sounds like it.