Lack of Power, Sluggish or Spongy
Checks
| Action
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DEFINITION: The 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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• | Verify that the engine control module (ECM) grounds are clean, tight, and in the correct locations. |
• | Remove the air filter element and inspect for restrictions and replace if necessary. |
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Fuel System
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• | Test or inspect items that can cause an engine to run rich. For a rich condition, refer to
DTC P0172
. |
• | Test or inspect items that can cause an engine to run lean. For a lean condition, refer to
DTC P0171
. |
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Sensor/System
| Use a scan tool in order to monitor the knock sensor (KS) system for excessive spark retard activity. Refer to
Knock Sensor (KS) System Description
.
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Ignition System
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• | Wet down the secondary ignition system with water from a spray bottle. Wetting the secondary ignition system may help locate damaged or deteriorated components. Look/listen for arcing or misfiring as water is applied. |
• | Remove the spark plugs and inspect for the following conditions: |
- | Refer to the following procedures: |
• | If the spark plugs are fouled by gas, coolant, or oil, determine the cause before replacing the plugs. Refer to the following procedures: |
- | For diagnosis of a rich condition, refer to
DTC P0172
. |
• | Test the crankshaft position (CKP) sensor for the correct resistance. The CKP sensor resistance may be out of range after a hot soak. The resistance should be between 460-620 ohms. |
• | Inspect the ignition coil for cracks or carbon tracking. |
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Engine Mechanical
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• | Inspect for excessive oil in the combustion chamber and for leaking valve seals. |
• | Inspect the combustion chambers for excessive carbon buildup. Clean the chambers with top engine cleaner. Follow the instructions on the can. |
• | Inspect the following for incorrect basic engine parts: |
- | The pistons, connecting rods, and bearings |
- | Refer to the following procedures in Engine Mechanical - 1.4L DOHC : |
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Additional Inspections
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• | Inspect the following exhaust system components: |
- | The exhaust system for physical damage. |
- | The mufflers for heat distress or possible internal failure. |
- | The three-way catalytic converter(s) for restrictions. |
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