Poor Fuel Economy

DEFINITION
Fuel economy, as measured by man 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 And Physical Checks" in Preliminary Checks. - Important Preliminary Checks
^ Check air cleaner (ACL) for dirt or being plugged.
^ Visually (physically) check vacuum hoses for splits, kinks, and proper connections as shown on underhood "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?

NOTE: Suggest owner fill fuel tank and recheck fuel economy. Suggest driver to read "Important Facts on Fuel Economy" in Owner's Manual.

ADDITIONAL CHECKS
^ Check Torque Converter Clutch (TCC) operation. Refer to Chart C-8A Torque Converter Clutch (TCC) Relay System Check. Testing and Inspection
^ Check for proper calibration of speedometer.
^ Check for dragging brakes.

FUEL SYSTEM
^ Check fuel pressure.

Refer to Chart A-7B Fuel System Pressure Check. Testing and Inspection

Also refer to On-Board Diagnostic System Check. Testing and Inspection

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.
^ Check ignition wires for cracking, hardness, and proper connections.
^ Check for proper operation of Electronic Spark Advance (ESA) system.
^ Check ignition timing. See underhood "Vehicle Emission Control Information" label.

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