Inspections
| Action
|
DEFINITION: Engine power variation under steady throttle or cruise. Feels like
the vehicle speeds up and slows down without a change in the accelerator pedal position.
|
Preliminary
|
| • | Ensure that the driver understands the operation of the transmission
torque converter clutch (TCC) and A/C compressor operation as explained in the owner's
manual. Inform the customer how the TCC and the A/C clutch operates. |
|
Sensor/System
|
Notice: Refer to Heated Oxygen and Oxygen Sensor Notice in the Preface section. | • | Inspect the heated oxygen sensor (HO2S) wiring for damage and/or poor connections. |
Notice: Refer to Silicon Contamination of Heated Oxygen Sensors Notice in the Preface section. | • | Inspect the HO2S for silicon or other contaminants. |
| • | Inspect the intake air ducts for proper installation and for leaks. |
| • | Inspect the mass air flow (MAF) sensor connections. Repair or replace
the terminals. Refer to
Connector Repairs
in
Wiring Systems. |
|
Fuel System
|
| • | Verify that each injector harness is connected to the correct injector/cylinder.
Relocate injector harnesses as necessary. |
| • | Test the items which can cause an engine to run rich (long term fuel
trim near -13 percent). For a rich condition, refer to
DTC P0172 or P0175
. |
| • | Test the items that can cause an engine to run lean (long term fuel trim
near 23 percent). For a lean condition, refer to
DTC P0171 or P0174
. |
|
Ignition System
|
| • | Inspect for proper installation of the ignition coil seal. Improper installation
may allow water to enter spark plug area. Inspect for moisture and corrosion. |
| • | Remove the spark plugs and inspect for the following conditions: |
| • | Determine the cause of the fouling before replacing the spark plugs if
the spark plugs are gas, coolant or oil fouled. Refer to
Spark Plug Inspection
. Once you determine the cause of the fouling,
refer to one of the following procedures: |
| - | For diagnosis of coolant contaminated spark plugs, refer to
Loss of Coolant
in Engine Cooling. |
|
Additional
|
| • | Visually/physically inspect vacuum hoses for splits, kinks, and proper
connections and routing as shown on the vehicle emission control information label.
Refer to
Emission Hose Routing Diagram
. |
| • | Inspect the exhaust system for the following conditions: |
| - | Damaged or collapsed pipes |
| - | Heat distress such as cracking or for an internal failure of the muffler |
| • | Test the transmission TCC operation. A TCC applying too soon
can cause the engine to spark knock. Refer to
Symptoms - Automatic Transmission
in Automatic Transmission. |
|
