Inspection/Tests
| Action
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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 position.
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Preliminary
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• | Verify the driver understands the operation of the transmission torque converter clutch (TCC) and A/C compressor operation as explained in the owners manual. |
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Sensor/System
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Notice: Refer to Silicon Contamination of Heated Oxygen Sensors Notice in the Preface section.
• | Inspect for proper operation of the manifold absolute pressure (MAP) sensor. Refer to
DTC P0106
. |
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Fuel System
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• | Verify that each fuel injector harness is connected to the correct fuel injector or cylinder. Relocate the fuel injector harnesses as necessary. |
• | Inspect for the following that may cause the engine to run rich: |
Notice: Refer to Heated Oxygen and Oxygen Sensor Notice in the Preface section. - | Water intrusion in the heated oxygen sensor (HO2S) connector |
- | Purging of a saturated evaporative emission (EVAP) canister |
- | Manifold absolute pressure (MAP) sensor operation--Refer to
DTC P0106
. |
- | Vacuum hoses that are split, kinked, or improperly connected |
- | An air intake duct that is collapsed or restricted |
• | Inspect for the following conditions that may cause the engine to run lean: |
Notice: Refer to Heated Oxygen and Oxygen Sensor Notice in the Preface section. - | Water intrusion in the HO2S connector |
- | An exhaust leak between the HO2S and the engine--Refer to
Exhaust Leakage
. |
- | Proper MAP sensor operation--Refer to
DTC P0106
. |
- | Vacuum hoses that are split, kinked, or improperly connected |
|
Ignition System
|
• | In order to properly inspect the spark plugs or to correct a condition, refer to the following procedures: |
• | Inspect for proper secondary ignition voltage output with the
J 26792
HEI Spark Tester. |
• | An improper spark plug gap will cause a driveability condition. Gap the spark plugs using a wire gage gap tool. |
• | If the spark plugs are found to be fouled, determine the cause before replacing the spark plugs. |
• | Monitor the Misfire Current Counters while driving the vehicle in the conditions that the symptom occurred. If a misfiring cylinder can be located, use the DTC P0300 table for diagnosis. Refer to
DTC P0300
. |
|
Engine Mechanical
| Inspect for excessive crankshaft endplay that will cause the crankshaft position (CKP) sensor reluctor wheel to move out of alignment with the CKP sensor. Refer to
Crankshaft and Bearing Cleaning and Inspection
. This could result in any of the following conditions:
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Additional Inspections
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• | Visually and physically inspect vacuum hoses for splits, kinks, and proper connections and routing as shown on the Vehicle Emission Control Information label. |
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