Lincoln F4SZ-9C968-A Fuel Pressure Regulator

Acting as a check valve, the regulator closes the restriction path when the fuel pump is off, trapping pressurized fuel for quick engine restarts.

Relieve fuel pressure, remove the air intake plenum assembly on 5.0L engines or the air intake assembly on 4.6L engines, and remove the fuel rail assembly. Detach the electrical connectors from the injectors, remove the injectors, inspect and replace injector O-rings and other components as needed. Lubricate new O-rings with oil before installation and twist to install the injectors. The remainder of the installation is the reverse of removal.

Proper regulator operation depends on an unobstructed fuel flow, an open return path, and a reliable vacuum signal from the intake manifold.

Continue by disconnecting the PCV system and, if present, the canister purge line and EGR spacer coolant lines, draining the coolant if needed. Remove the six upper intake manifold retaining bolts and lift off the upper intake manifold and throttle body as an assembly from the lower intake manifold.