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.