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 EGR system in "Testing
Flange gasket leaking, Procedures" in Emissions, if OK, step 2
solenoid malfunctioning 2. Check EGR electronic controls in
"Fuel Injection & Computerized Engine Controls"




Ignition timing Check Ignition Timing in "Adjustment
Procedures" in Emissions



Spark timing Check Spark Controls (SCC) in
"Testing Procedures" in Emissions



Air management valves Check Air Injection system in
"Testing Procedures" in Emissions



Air damper door binding, Check inlet air temperature system (HIAS)
air cleaner temperature in "Testing Procedures" in Emission
control malfunction



Restricted exhaust Check Catalytic Converter in
"Testing Procedures" in Emissions