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 car at one time, as previously shown by an actual road test.

^ Check owners 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?
^ Start with Flow of Diagnosis first.
^ Check for proper operation of TCA.
^ Check air cleaner element (filter) for dirt or restricted air flow.
^ Check for proper calibration of speedometer.
^ Visually (physically) Check:
- Vacuum hoses for splits, kinks or improper connections.
- Ignition wires for cracking, hardness or improper connections.
^ Check ignition timing. See Vehicle Emission Control Information label. If "Scan" tool is available, check for excessive retard.
^ Remove spark plugs. Check for cracks, wear, improper gap, burned electrodes or heavy deposits. Repair or replace as necessary.
^ Check for fuel leaks.
^ Check for excessive blow-by and excessive crankcase pressure.
^ Check compression.
^ Check for dragging brakes.
^ Check for exhaust system restriction.