Poor Fuel Economy

DEFINITION
Fuel economy, as measured by an actual road test, is noticeably lower than expected. Also, economy is noticeably lower than it was on this vehicle at one time, as previously shown by an actual road test

PRELIMINARY CHECKS
^ Perform the careful visual/physical checks as described in Preliminary Checks.

^ Visually (physically) check vacuum hoses for splits, kinks, and proper connections as shown on "Vehicle Emission Control Information" label.
^ Check owner's driving habits.
- Is A/C "ON" full time (Defroster mode "ON")?
- Are tires at correct pressure?
- Are excessively heavy loads being carried?
- Is acceleration too much, too often?

^ Check air cleaner filter for dirt or being plugged.

IGNITION SYSTEM
^ Check spark plugs. Remove spark plugs, check for wet plugs, cracks, wear, improper gap, burned electrodes, or heavy deposits. Repair or replace as necessary.

COOLING SYSTEM
^ Check engine coolant level
^ Check engine thermostat for faulty part (always open) or for incorrect heat range.

ENGINE MECHANICAL
^ Perform cylinder compression test.

FUEL SYSTEM
^ Fuel pressure. Refer to Chart A-7. Related Tests, Information and Procedures

ADDITIONAL CHECKS
^ Check [1][2]Torque Converter Clutch (TCC) for proper operation. A Tech 1 scan tool should indicate an RPM drop, when the TCC is commanded "ON" (if equipped). Refer to Chart C-8. Chart C-8 Transmission Diagnosis

^ Check for exhaust system restriction. Refer to Chart B-1. B Charts

^ Check for proper calibration of speedometer.
^ Check induction system and crankcase for air leaks.
^ Suggest driver read "Important Facts on Fuel Economy" in "Owner's Manual."