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 check 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 element (filter) for being restricted.

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, use Chart C-16. Testing and Inspection
Engine thermostat for faulty part or for wrong heat range.

ENGINE MECHANICAL
Check:
Compression.

ADDITIONAL CHECKS
Check:
Proper Torque Converter Clutch (TCC) operation.
For exhaust system restriction, use CHART B-1. Testing and Inspection
For proper calibration of speedometer.
Air intake system and crankcase for air leaks.