96 Buick Rivera 3.8 Vin K car will not run rough idle the stalls

Question

fuel pump replaced, rail and regulator replaced, new plugs and wires, fuel pressure 30 - start engine fuel pressure goes to 80 misses like crazy, then stalls. Injectors were replace also two months ago. Car will run good for a week then back to this again.

Answer 1

The fuel pressure specification for this vehicle is 48 - 55 psi, The fuel pressure 80 psi?  Even if you disconnect the vacuum hose to the fuel pressure regulator it will not go that high.or plugging the fuel return lines  The fuel pump putting out this amount of pressure the problem  will be with the fuel pump.