Checks
| Action
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Definition:
Fuel economy, as measured by an actual road test, is noticeably lower than
expected. Also, the economy is noticeably lower than it was on this vehicle
at one time, as previously shown by an actual road test.
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Preliminary Checks
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| • | Refer to Important Preliminary Checks. |
| • | Check air cleaner filter for dirt or being plugged. |
| • | Visually (physically) check: Vacuum hoses for splits, kinks, and
proper connections. |
| • | Perform Powertrain On-Board Diagnostic System Check. |
| • | Check owners driving habits. |
| • | Is A/C ON full time (Defroster mode ON)? |
| • | Are tires at correct pressure? |
| • | Are excessively heavy loads being carried? |
| • | Is acceleration too much, too often? |
| • | Suggest owner fill fuel tank and recheck fuel economy. |
| • | Suggest driver read 'Important Facts on Fuel Economyin Owners
Manual. |
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Fuel System
Checks
|
| • | Check the fuel type, quality. Refer to Diagnosis in Fuel Systems. |
| • | Check the fuel pressure. Refer to Table A-5in Control Modulel
Systems. |
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Cooling
System Checks
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| • | Check the engine coolant level. |
| • | Check the engine thermostat for always being open or for the wrong
heat range. |
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Additional
Checks
|
| • | Check the transmission shift pattern. |
| • | Check the Torque Converter Clutch (TCC) operation. When the TCC
is commanded ON, a scan tool should indicate an RPM drop. |
| • | Check the Service Bulletins for control module software updates. |
| • | Check for dragging brakes. Refer to the appropriate service manual. |
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