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 element (filter) for dirty or being plugged.

IGNITION SYSTEM
Check the 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 wrong heat range.

ENGINE MECHANICAL
Check compression.

ADDITIONAL CHECKS
- Check [1][2]Torque Converter Clutch (TCC) operation. Use Chart C-5. Testing and Inspection
The engine speed display on a Tech 1 should indicate an RPM drop when the TCC is commanded "ON."
- Check For exhaust system restriction. Use Chart B-1. B Charts
- Check For proper calibration of speedometer.
- Check Induction system and crankcase for air leaks.