fuel pump problems on a 96 gt

[ZornLack11]

my father in law has a 96 gt and has a problem with the fuel pump. it seems sometime it works and sometimes it dont. we have replace it with a new one checked all the wiring, put it back in and test it before putting the tank back in and it works. put the tank back in and it stops. i have lost count on how many times we have pulled the tank in and out. any ideals thanks

[MADMOD]

If I had to take a stab at it, it almost sounds like you are pinching a fuel line or wire when you put the tank back in. I would also make sure there are no bare wires in that could short out.