Get a fuel pressure gauge and connect it to the rail for the fuel injectors to read pressure.
If the pressure is too low, it might be a bad fuel pressure regulator or pump:
Fuel Pressure Regulator
Removal & Installation
2.2L Engine
To Remove:
- Relieve the pressure in the fuel system.
- Disconnect the negative battery cable.
- Disconnect the vacuum hose from the fuel pressure regulator.
- Remove the pressure regulator mounting screw.
- Remove the fuel pressure regulator assembly with O-ring. Inspect filter screen for contamination. If contaminated, remove and discard.
Fuel pressure regulator removal/installation (2.2L SFI engine)
To Install:
- Apply clean engine oil to the new pressure regulator O-ring and install the O-ring on the regulator.
- Install the regulator on the fuel rail. Apply thread-locker to the mounting screw.
- Tighten the screw to 106 lb in (12Nm).
- Connect the negative battery cable.
- Use the following procedure to pressurize the fuel system and check for leaks;
- Turn the ignition ON for 2 seconds.
- Turn the ignition OFF for 10 seconds.
- Turn the ignition switch back ON to run the fuel pump again and pressurize the fuel system.
- Check the fuel rail assembly for fuel leaks.
4.3L Engine
RPO L35
To Remove:
4.3L (RPO L35) Fuel meter body assembly
- Before servicing the vehicle, refer to the Cautions and Warnings in the beginning of this section
- Remove or disconnect the following:
- Upper intake manifold (See: Upper Intake Manifold)
- Fuel pressure regulator retainer clip (M) and discard the clip
- Regulator (N) from the housing by twisting and pulling the fuel pressure regulator (N) and using a shop towel to catch any spilled fuel
- Regulator seal O-ring (R) and discard the O-ring seal
- Regulator filter (Q) and discard the filter
- Regulator seal O-ring (P) and discard the O-ring seal
- Backup ring (O) and discard the ring
- Cover the fuel pressure regulator housing to prevent contamination from entering the fuel system
To Install:
4.3L (RPO L35) Fuel meter body assembly
- Lubricate the NEW O-ring seals with clean engine oil
- Assemble the following new parts to the fuel pressure regulator:
- Backup ring (O)
- Regulator seal O-ring (P)
- Regulator filter (Q)
- Regulator seal O-ring (R)
- Install or connect the following:
- Fuel pressure regulator with the vacuum tube pointing down
- Fuel pressure regulator retainer clip (M)
- Upper manifold
- Test drive the vehicle to confirm the repairs
RPO LU3
To Remove:
4.3L (RPO LU3) Fuel meter body assembly
- Before servicing the vehicle, refer to the Cautions and Warnings in the beginning of this section
- Remove or disconnect the following:
- Upper intake manifold
- Fuel pressure regulator retainer clip (E)
- Regulator (F) from the housing by twisting and pulling the fuel pressure regulator (F) while using a shop towel to catch any spilled fuel
- Regulator seal O-ring (J) and discard the O-ring seal
- Regulator filter (I) and discard the filter
- Regulator seal O-ring (H) and discard the seal
- Backup ring (G) and discard the backup ring
- Cover the fuel pressure regulator housing to prevent contamination from entering the fuel system
To Install:
4.3L (RPO LU3) Fuel meter body assembly
- Lubricate the NEW O-ring seals with clean engine oil.
- Assemble the following new parts to the fuel pressure regulator:
- Backup ring (G)
- Regulator seal O-ring (H)
- Regulator filter (I)
- Regulator seal O-ring (J)
- Install or connect the following:
- Fuel pressure regulator (F) with the vacuum tube pointing down
- Fuel pressure regulator retainer clip (E)
- Upper intake manifold
- Test drive the vehicle to confirm the repairs
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