1993 Oldsmobile Cutlass fuel

Put a new fuel in the tank an the car ran for a month fine.Then the car quit again wasn't getting fuel,there was no fuel pressure,took the fuel pump out again its working fine out of the tank ,tryed everything to get the pump to shut off while out if the fuel tank,shaking plug-ins checking relays which checked ok,put the pump back in the car ran great for 2 days an quit again,no fuel pressure,2 days later the car starts an quits again.
You have any ideals will a computer test find the problem
thanks