Poor Fuel Economy

SYMPTOM DESCRIPTION:
From an actual road test the measured MPG is noticeably lower than expected. At one time the fuel economy for this vehicle was at a greater average than current measurement. Check the following systems and components.



FUEL
^ FUEL TYPE: quality and alcohol content.
^ FUEL PRESSURE: Check for restricted fuel return line or defective pressure regulator.



COMPUTER INPUTS/OUTPUTS
^ DME CONTROL UNIT: Check for correct control unit and PROM I. D.
^ FUEL INJECTORS: Poor spray pattern, or sticking. Refer to Fuel Injector,
^ OXYGEN SENSOR:
^ AIR FLOW METER: Defective



IGNITION
^ SPARK PLUGS. Remove spark plugs, check for wet plugs, cracks, wear, improper gap, burned electrodes, or heavy deposits. Repair or replace as necessary.




COOLING
^ For obvious over heating problems.
^ AUXILIARY COOLING FAN:
^ FAN CLUTCH: Operation.
^ Low engine coolant level and leaks.
^ WATER PUMP: Loose belts?
^ Restricted air flow to radiator or restricted coolant flow.
^ THERMOSTAT: Faulty or incorrect.
^ Correct coolant solution - should be a 50/50 mix of anti-freeze (coolant) and water.



MECHANICAL - ENGINE/TRANSMISSION
^ Transmission shift pattern.
^ COMPRESSION:
^ Clutch slipping
^ For proper calibration of speedometer.
^ For dragging brakes.
^ For proper tire inflation.