On this vehicle, the system is a mechanical return less fuel system (MRFS). The fuel pressure regulator, in this case, is in the fuel tank and part of the fuel pump module.
Here is the definition from the manual:
The fuel pump (FP) module contains the fuel pump, the fuel pressure regulator, and the fuel sender assembly. The fuel pressure regulator is attached to the FP module and regulates the pressure of the fuel supplied to the fuel injectors. The fuel pressure regulator controls the pressure of the clean fuel as the fuel returns from the fuel filter. The fuel pressure regulator is a diaphragm-operated relief valve. Fuel pressure is established by a spring preload applied to the diaphragm. The FP module is located in the fuel tank.
As far as the fuel issue, do you have a live data scan tool? If you do, I need you to check two things. First, check the short-term fuel trims. Also, when the engine is cold, check the coolant temperature sensor signal. It should be the same or very close to the ambient temperature. If it is on the extreme end of "cold", that could be causing the computer to run an extremely rich fuel mixture.
Let me know if this helps and if you can perform the test.
Friday, December 17th, 2021 AT 7:46 PM