Poor Fuel Economy

Fuel economy is noticeably lower than expected. Customer detects a significant reduction in fuel mileage.

POSSIBLE CAUSE ACTION


EGR malfunction, Check EGR system
Flange gasket leaking, Refer to TESTING PROCEDURES.
solenoid and thermo valves
malfunctioning



Ignition timing Refer to COMPUTERS AND CONTROL SYSTEMS.



Spark timing Check Spark Controls. Refer to COMPUTERS AND CONTROL SYSTEMS.



Air management valves Check Air Injection system. Refer to TESTING PROCEDURES.




Restricted exhaust Check Catalytic Converter. Refer to TESTING PROCEDURES.