Checks
| Action
|
DEFINITION: The
engine has a power variation under a steady throttle or cruise. The vehicle
feels as if it speeds up and slows down with no change in the
accelerator pedal position.
|
Preliminary Checks
|
| • | Be sure the driver understands the torque converter clutch operation. |
| • | Be sure the driver understands the A/C compressor operation. |
| • | Use the scan tool in order to make sure the reading of the vehicle
speed sensor (VSS) matches the vehicle speedometer. This excludes vehicles
with electronic transmissions where some variation between the
VSS and the speedometer is normal. |
| • | Ensure that the transmission fluid is at the proper level. |
|
Sensor Check
| Display the scan tool parameters for the various engine controls sensors.
Check for any abnormal readings.
|
Fuel System Checks
|
| • | Check for a rich or lean symptom that causes the condition. Drive
the vehicle at the speed of the complaint. Monitoring the fuel trim will help
identify the problem. |
| • | Lean -- The long term fuel trim will be more than 150. |
| • | Rich -- The long term fuel trim will be less than 115. |
| • | Check the in-line fuel filter for a restrictions. |
|
Ignition System Checks
|
| • | Check the secondary ignition system and spark plugs. Remove the
plugs and inspect them for the following conditions: |
| • | Check the crankshaft position (CKP) sensor. |
|
Additional
Checks
|
| • | Check the control module grounds for being clean, tight, and in
their proper locations. |
| • | Check the generator output voltage. |
| • | Check the vacuum hoses for kinks or leaks. Refer to the Vehicle
Emission Control Information label. |
|
