Poor Fuel Economy

Fuel economy is noticeably lower than expected. Customer should drive vehicle and note miles per gallon decrease.

POSSIBLE CAUSE ACTION


EGR malfunction, 1. Check the EGR system under TESTING
Flange gasket leaking, PROCEDURES. If OK, step 2
solenoid malfunctioning 2. Check the EGR electronic controls.
Refer to COMPUTERIZED ENGINE CONTROLS.




Ignition timing Check the Ignition Timing under
ADJUSTMENT PROCEDURES.



Spark timing Check the Spark Controls (SCC).
Refer to COMPUTERIZED ENGINE CONTROLS.



Air management valves Check the Air Injection system under
TESTING PROCEDURES.



Air damper door binding, Check the Inlet Air Temperature System
air cleaner temperature under TESTING PROCEDURES.
control malfunction



Restricted exhaust Check the Catalytic Converter
under TESTING PROCEDURES.