FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.

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