Inspection/Tests
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DEFINITION: Engine delivers less than expected power. Little or no increase in speed when the accelerator pedal is pushed down part way.
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Preliminary Inspections
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Fuel System
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Sensor/System
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• | 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. - | Any water intrusion in the heated oxygen sensor (HO2S) connector |
- | The engine oil contaminated by fuel |
- | An evaporative emission (EVAP) canister purge condition |
- | Any vacuum hoses that are split, kinked, or improperly connected |
• | 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. - | Any water intrusion in the HO2S connector |
- | An exhaust leak between the HO2S and the engine--Refer to
Restricted Exhaust in Engine Exhaust. |
- | Any vacuum hoses that are split, kinked, or improperly connected |
• | Use a scan tool in order to monitor the knock sensor (KS) system for excessive spark retard activity. Refer to
Scan Tool Data List . |
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Ignition System
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• | In order to properly inspect the spark plugs or to correct a condition, refer to the following procedures: |
• | Remove spark plugs and inspect for the following conditions: |
- | Verify that the spark plugs are of the correct type. |
• | Inspect for proper 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. |
• | Determine the cause of the fouling before replacing the spark plugs. |
• | Inspect for damaged or misaligned spark plug boots. |
• | Inspect the electronic ignition (EI) module for proper ground connection. |
• | 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 . |
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Engine Mechanical
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• | Inspect for incorrect camshaft timing. |
• | Inspect for excessive oil in the combustion chambers and leaking valve seals. Refer to
Oil Consumption Diagnosis in Engine Mechanical. |
• | Inspect for incorrect basic engine parts, including the following components: |
• | 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 in Engine Mechanical. This could result in any of the
following conditions: |
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Additional Inspections
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• | Inspect the exhaust system for the following possible restrictions: |
- | The exhaust system for damaged or collapsed pipes |
- | The mufflers for heat distress or internal failure |
• | Inspect the transmission torque converter clutch (TCC) for proper operation. Refer to
Torque Converter Diagnosis in Automatic Transaxle - 4T40-E/4T45-E. |
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