hatch302

got a 91 5.0 EFI stang. started up fine then just shut off. turned the key to start position and all i heard was the fuel pump humming non stop. next day comes around...and now the pump has stopped completely. bought a new 255lph pump installed it...nothing. bought a new fuel pump relay and still nothing. everything is normal as far as what happens when starting the car but no sound from the pump and as a result no firing of the engine. maybe a sour sensor someplace?? anyone have any input before i have it towed the local dealership to get it repaired?[X(]