Poor Fuel Economy
Fuel economy is noticeably lower than expected. Customer should drive vehicle and note miles per gallon decrease.
POSSIBLE CAUSE ACTION
Incorrect spark advance Check Spark Controls,
Restricted exhaust Check Catalytic Converter, Catalytic Converter
Incorrect Air-Fuel mixture Check Air-Fuel ratio, perform injector balance test, inspect regulator operation (check vacuum line and return hose), check fuel pressure
EGR malfunction Check EGR system, Exhaust Gas Recirculation
Air filter restricted Clean or replace
Poor or contaminated fuel Recommend higher grade fuel