Poor Fuel Economy

WARNING: This page is about a different car, the 2000 Ford Pickup, 2000 Ford F550 Super Duty, 2000 Ford F450 Super Duty, 2000 Ford Contour, and 2000 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Fuel consumption can be increased during stop-and-go driving, trailer towing, short-run operation, extended winter warm-up periods, improper tire inflation, high speed driving, improper axle ratio and aftermarket add-ons. Determine if these factors are the cause of poor fuel mileage before proceeding with diagnostic procedure.

Check the following PID values: DPFEGR, LONGFT 1, LONGFT 2 and VPWR. See PIN VOLTAGE/PID VALUE CHARTS article. On some models, DPFEGR PID may not be applicable. DPFEGR PID value should be within .15 volt of Key On Engine Off (KOEO) value. If LONGFT 1 or LONGFT 2 PID value is low (-20 percent), concentrate checks in areas that would cause engine to run rich. If LONGFT 1 or LONGFT 2 PID value is high (+20 percent), concentrate checks in areas that would cause engine to run lean. If VPWR PID voltage is not 10.5-17.0 volts, check charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. If VPWR PID voltage is 10.5-17.0 volts but not within .5 volt of battery voltage, check battery supply to power relay (or CCRM) and VPWR circuit between PCM and power relay or CCRM, and PWR GND circuits. See WIRING DIAGRAMS article.
Check A/T Torque Converter Clutch (TCC) and/or TCC solenoid for proper operation. See appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS.
Check PCV system. See TEST HG under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article.
Check cooling system for overheating. If cooling system is overheating, repair as necessary. See appropriate article in ENGINE COOLING.
Check secondary ignition system. See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article.
Check air intake system, see TEST HU under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article.
Check fuel delivery system. See TEST HC under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (BI-FUEL) article.
Check exhaust system. See TEST HF under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article.
Check engine mechanical condition. Check intake manifold gasket, camshaft and valves and repair as necessary. See appropriate article in ENGINES.
Check for dragging brakes and repair as necessary. See appropriate article in BRAKES.
If no problems are indicated, return to SYMPTOM DIAGNOSIS to identify any additional symptoms or see TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article and check for intermittent faults.