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.




SYSTEM OR COMPONENT TO CHECK ACTION

FUEL CHECK: - FUEL TYPE, quality and alcohol content.
- FUEL PRESSURE



IGNITION CHECK: - SPARK PLUGS:
Remove spark plugs, check for wet plugs,
cracks, wear improper gap, burned electrodes,
or heavy deposits. Repair or replace as necessary.
- IGNITION WIRES for cracking, hardness, and
proper connections.
- SPARK CONTROL operation.
- IGNITION TIMING.



COOLING CHECK: - For obvious over heating problems.
- Low engine coolant level and leaks.
- Water pump operation, loose belts
- Restricted air flow to radiator or
restricted coolant flow.
- Faulty or incorrect thermostat.
- Correct coolant solution - should be a 50/50
mix of anti-freeze (coolant) and water.
- Fan operation (electric or belt driven).





MECHANICAL - ENGINE/TRANSMISSION CHECK: - Transmission shift pattern.
- TCC operation. A "Scan" tool should indicate an
rpm drop when the TCC is commanded "ON."
- For proper calibration of speedometer.
- For dragging brakes.
- For proper tire inflation.