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.
|
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 (HO2) sensors. The HO2 sensors should
respond quickly to different throttle positions. If they do not, check the
HO2 sensor 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 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. |
|
