Lack of Power, Sluggish or Spongy
Inspection/Tests
| Action
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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 HO2S connector |
- | The engine oil contaminated by fuel |
- | An 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
(SA9199Z) 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: |
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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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