Here's an overview of the fuel system on your truck and how it basically works.
FUEL DELIVERY SYSTEM - GASOLINE POWERED ENGINES
The fuel delivery system consists of:
- the fuel pump module containing the electric fuel pump, fuel filter/fuel pressure regulator, rollover valve (certain modules), fuel gauge sending unit (fuel level sensor) and a separate fuel filter located at bottom of pump module
- fuel tubes/lines/hoses
- quick-connect fittings
- fuel injector rail
- fuel injectors
- fuel tank
- fuel tank filler/vent tube assembly
- fuel tank filler tube cap
- accelerator pedal
- throttle cable
Fuel is returned through the fuel pump module and back into the fuel tank through the fuel filter/fuel pressure regulator. A separate fuel return line from the engine to the tank is not used with any gasoline powered engine.
The fuel tank assembly consists of: the fuel tank, fuel pump module assembly, fuel pump module locknut/gasket and rollover valve(s) (Refer to Emission Control System for rollover valve information)
A fuel filler/vent tube assembly using a pressure/vacuum fuel filler cap is used. On vehicles equipped with the California emissions package, the fuel filler tube contains a spring-loaded flap (door) located below the fuel fill cap. The flap is used as a secondary way of sealing the fuel tank if the fuel fill cap has not been properly tightened. It is part of EVAP monitor system when vehicle is equipped with a Leak Detection Pump (LDP)
Also to be considered part of the fuel system is the evaporation control system. This is designed to reduce the emission of fuel vapors into the atmosphere. The description and function of the Evaporative Control System is found in Group 25, Emission Control Systems.
Both fuel filters (at bottom of fuel pump module and within fuel pressure regulator) are designed for extended service. They do not require normal scheduled maintenance. Filters should only be replaced if a diagnostic procedure indicates to do so.