Q: Cannot find fuel pressure regulator under the hood of my 2001 f150xl V6 4.2

The fuel pressure regulator is beneath the upper intake manifold. That manifold has to be removed to gain access. Once you remove the manifold, you will see the regulator connected to the fuel rail and one end of the regulator has a vacuum attachment that connects to the intake manifold. Fuel is under high pressure even when the vehicle is off so if working on the system be sure to follow the Factory Service Manual precautions. If you need service on the fuel system and/or regulator replacement performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request fuel system pressure regulator service. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.