i am sending you this picture and information just to show you that the fuel pump pressure should be more then 20 psi , the reason for the engine lights and codes is because the low fuel pressure problem is affecting other sensors like 02 sensor and map sensor
Fuel Pressure Regulator Operation: The pressure regulator is a mechanical device that is calibrated to maintain fuel system operating pressure of approximately 338 kPa (49 psi) at the fuel injectors.It contains a diaphragm, calibrated springs and a fuel return valve. The internal fuel filter (Fig. 2) is also part of the assemblyFuel is supplied to the filter/regulator by the electric fuel pump through an opening tube at the bottom of filter/regulator.The fuel pump module contains a check valve to maintain some fuel pressure when the engine is not operating. This will help to start the engine.If fuel pressure at the pressure regulator exceeds approximately 49 psi, an internal diaphragm closes and excess fuel pressure is routed back into the tank through the pressure regulator. A separate fuel return line is not used with any gas powered engine.
yeah i have a volt ohm meter i have checked voltage at the fuel pump at the key on position and it is at 12 volts
it has 12 volts briefly then fluctates after testing this i checked and replaced the relays bothe fuel and auto shutdown relay
voltage at the battery is 14.52 volts when engine is running
ok at the fuel pump fuse i have just over 14 volts
and at the fuel pump it goes from 12 to an average of 10
i just checked all wires at the fuel pump one has 13 volts one has 10 the other has 10 and on has 9
what is the voltage at dose 2 wires that have power?
one last voltage check , disconect the fuel pump and with key on check power.
ok, we cover all the basis of posible fuel restrictions and electrical flows and found no problems but still cant explane the lost of presure, one last thing we can do is baypass the circuit and run a wire strait from the positive side of the battery, and another wire for grownd start the car and check fuel presure again.