1995 Pontiac Grand Prix Starts with starter fluid then shut

Its a 95 pontiac SE and it just died while I was driving it. We changed the crank positioning sensor, and fuel filter. But it still wont start. It will start with starter fluid but then shuts off when it burns it up. So im assuming that its not getting fuel some how cause it will run with the fluid. Someone suggested the fuel pressure might be low. And the fuel pump turns on when you turn the key. Any help or advice would be appreciated. Thank you.