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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• | Inspect both injector fuses for being open. An open injector fuse causes
four ignition coils and four injectors not to operate. Replace the fuse.
Inspect the ignition coil circuits and the injector circuits for an intermittent short
to ground. |
• | 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. |
- | Engine oil contaminated by fuel. |
- | An evaporative emission (EVAP) canister purge condition. |
- | An inaccurate mass air flow (MAF) sensor. |
- | Vacuum hoses that are split, kinked, or incorrectly 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 |
- | An inaccurate MAF sensor. |
- | Vacuum hoses that are split, kinked, or incorrectly connected. |
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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
Customer Concern Verification Sheets .
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Ignition System
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• | Verify that both fuel injector fuses are not open. An open fuel injector
fuse causes 4 ignition coils and 4 fuel injectors not to operate. Inspect
the ignition coil circuit and the injector circuits for an intermittent short to ground.
Refer to
Circuit Testing . Replace the fuse. |
• | Soak the secondary ignition system with water from a spray bottle. Soaking
the secondary ignition system may help locate damaged or deteriorated components.
Look and listen for arcing or misfiring as water is applied. |
• | Inspect for proper ignition voltage output with the
J 26792 Spark Tester. |
• | Remove the spark plugs and inspect for the following: |
Refer to
Spark Plug Inspection .
• | An incorrect spark plug gap will cause a driveability problem. Gap the
spark plugs using a wire gage gap tool. Refer to
Spark Plug Replacement . |
• | Determine the cause of the fouling before replacing the spark plugs. |
• | Monitor the Misfire Current Counters while driving the vehicle within
the conditions that the misfire occurred. If a misfiring cylinder can be located with
a misfire, use the DTC P0300 table for diagnosis. Refer to
DTC P0300 . |
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Engine Mechanical
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• | Verify that the engine coolant temperature (ECT) is not above 130°C
(266°F). This condition causes the ECM to operate in Engine Coolant Over Temperature-Fuel
Disabled Mode. While in Engine Coolant Over Temperature-Fuel Disabled Mode, the ECM
will disable the fuel injectors to four cylinders at a time to keep engine
temperatures from reaching damaging levels. The driver may perceive the Engine Coolant
Over Temperature-Fuel Disabled Mode as a lack of power, miss, or rough idle. If the
vehicle operates in Engine Coolant Over Temperature-Fuel Disabled Mode, refer
to
Engine Overheating
. |
• | Inspect for incorrect basic engine parts, including the following: |
• | 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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• | Inspect the exhaust system for possible restrictions. Perform the following: |
- | Inspect the exhaust system for damaged or collapsed pipes. |
- | Inspect the mufflers for heat distress or internal failure. |
• | Inspect the transmission torque converter clutch (TCC) for proper operation. |
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