Poor Fuel Economy

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

POSSIBLE CAUSE ACTION


Incorrect initial timing ^ Check base timing.
SEE IGNITION SYSTEM/ ADJUSTMENT PROCEDURES.

^ Check Timing belt alignment.


Incorrect spark advance ^ Check spark controls.
SEE IGNITION SYSTEM/ TIMING SPECIFICATIONS


Incorrect Air-Fuel mixture ^ Check fuel pressure.
^ Check O2 sensor.

^ Perform injector balance test (SFI only).


EGR malfunction ^ Check EGR system.
Exhaust Gas Recirculation


Poor or contaminated fuel ^ Recommend higher grade fuel