Poor Fuel Mileage

If fuel economy is lower than expected during an road test or has changed from previous road tests, check the following items:

• Check thermostat operation and heat range.
• Verify vehicle operation conditions; A/C always on, correct tire pressure, vehicle heavily loaded or constant heavy acceleration.
• Perform Diagnostic Circuit Check, see SELF-DIAGNOSTICS article.
• Check air cleaner condition.
• Check speedometer calibration.
• Perform a visual inspection of all vacuum hoses and ignition wires.
• Ensure ignition timing is correct.
• Check spark plugs for wear or damage.
• Ensure engine compression is correct.
• Ensure torque converter clutch operation is correct. See I - SYS/COMP TESTS article.
• Check brakes for dragging.
• Check exhaust system for restrictions.
• Re-check fuel mileage.