[A26B]

One obvious problem is your low fuel pressure.

Have you performed the static test (key on, engine off) individually, for each of your fuel pumps?

If the static test is still low, I suggest you remove the Fuel Pump Sender Assembly & inspect all the hoses & components for breaks or leaks.

If the inspection didn't reveal any leakage, then it may be one or both of the fuel pumps. Observe static fuel pressure. With Key on, Engine off, pressurize the fuel rail, turn key off and see how long it takes for the pressure to bleed off. Fast bleed down would indicate fuel pump check valve failure.

If the static test result is within spec, then disconnect the vacuum line from the FPR & plug the vacuum line. Start engine & observe the pressure. If the pressure is low again, then the regulator is at fault.