Surges and/or Chuggles Symptom
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.
|
Preliminary Checks
|
• | Be sure the driver understands the A/C compressor operation. |
• | Use a scan tool to make sure the reading of the vehicle speed
sensor (VSS) matches the reading of the instrument panel speedometer. Transmission
performance can be affected by incorrect VSS readings. If accuracy of
the VSS is a concern, refer to
Speedometer and/or Odometer Inaccurate or Inoperative
in Instrument Panel,
Gauges, and Console. |
|
Sensor
Checks
|
• | Check the heated oxygen sensors' (HO2S 1 and HO2S 2)
performance. Refer to the Diagnostic Aids for
DTC P0130
. |
• | Inspect the mass air flow (MAF) sensor operation. Run the engine
to normal operating temperature. Turn OFF all accessories and observe the
MAF sensor at idle with a scan tool. If the MAF sensor reading is more
than 3.5 g/s refer to
DTC P0101
. |
• | Check for correct operation of the engine coolant temperature
(ECT) sensor. A fixed or inaccurate ECT sensor reading can cause the engine
to surge, especially at low speeds and at stops. |
|
Fuel
System Checks
|
• | Determine if a rich or lean system can cause the condition. Drive
the vehicle at the speed of the complaint. Monitoring the Fuel Trim may help
identify the problem. |
- | Lean -- The Long Term Fuel Trim will be more than 20 percent.
Refer to Diagnostic Aids. |
- | Rich -- The Long Term Fuel Trim will be less than -20 percent.
Refer to Diagnostic Aids. |
• | Check the fuel injectors. Perform the following procedures: |
|
Ignition
System Checks
|
• | Check for the proper secondary voltage output with a J 26792
spark tester. |
• | Inspect the spark plugs for correct operation and good ignition
system performance. Refer to
Spark Plug Inspection
. |
|
Additional
Checks
|
• | Check the PCM grounds for being clean, tight, and in the proper
locations. Refer to
Power and Ground
. |
• | Check the generator for the correct output voltage. |
• | Check the vacuum lines and hoses for leaks or incorrect routing. |
• | Inspect for correct operation and correct shifting of the transmission.
Inspect for correct engagement of the torque converter clutch.
Symptoms - Automatic Transmission
in Automatic
Transmission. |
|