My friend has a 1993 F**d Tempo with a recurrung problem. He seems to have a problem with intermittant fuel flow. AT times he can hear the fuel pump activate when he turns the key (at that time the car WILL start and run), and at other times, the pump is dead. The pump has been replaced several times with the original Ford part. His mechanic is stumped. Any ideas? Is there a control command to the pump controlled by the on board computer? Thanks for any help.

Bad relay?