Poor Fuel Economy
- Check for slipping clutch or transmission.
- Check for dragging brakes.
- Check odometer calibration.
- Check vacuum system for leaks and routing.
- Check air intake system.
- Check fuel delivery system. See CIRCUIT TEST HC in TESTS W/CODES article.
- Check ignition system. See CIRCUIT TEST JB in TESTS W/CODES article.
- Check for restricted exhaust system.
- Check EGR system. See CIRCUIT TEST HE in TESTS W/CODES article.
- Check cooling system.
- Vehicle load, driving habits, road and weather conditions can also effect fuel economy.