Why does my engine die after running 10 seconds but will restart & run for 10sec on 1993 Mazda Protege

The car starts with no problem and runs perfect for about 10 seconds then it dies. It seems like it runs out of fuel. I installed a new fuel pump. Jumping the diagnostic box and the pump runs and generates 48PSI but when the engine runs there is less than 20PSI. I installed another pressure regulator but nothing changed. I wonder if a bad vacuum solenoid would cause this condition? I'm not certain how to test for that.

Asked by for the 1993 Mazda Protege