Checks
| Action
|
DEFINITION: Engine power variation under steady throttle
or cruise. Feels like the vehicle speeds up and slows down with
no change in the accelerator pedal.
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Preliminary
|
Be sure that the driver understands the transmission torque converter
clutch (TCC), and A/C compressor operation as explained in the owners
manual. Inform the customer how the TCC and the A/C system operate.
|
Sensor/System
|
| • | Check the heated oxygen sensors (HO2S)s. The HO2Ss should respond
quickly to different throttle positions. If they do not, check the
HO2S for the following conditions: |
| - | Contaminants from the fuel |
| - | The sensors may have a white powdery coating. This will result in a
high but false signal voltage (rich exhaust indicated). The powertrain
control module (PCM) will reduce the amount of fuel delivered
to the engine causing a severe driveability condition. |
| • | Check the mass air flow (MAF) sensor and intake air system for
proper connections. |
| • | Check the exhaust gas recirculation (EGR) system for proper operation. |
|
Fuel System
|
| • | Check for conditions which can cause an engine to run rich and/or
lean. |
|
Ignition System
|
| • | Check for proper ignition voltage output using the J 26792
Spark Tester. |
| • | Check for damaged ignition coils within the ignition coil module
assemblies. |
| • | Check for damaged or misaligned spark plug boots. |
| • | Check for a missing or damaged ignition module ground spring. |
|
Additional Checks
|
| • | Inspect the vacuum hoses for splits, kinks, and improper connections
or routing. |
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