Definition: Engine delivers less than expected power. Little or no increase in speed when accelerator pedal is pushed down part way.

Was the Powertrain On-Board Diagnostic(OBD) System Check performed?

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Go to Step 2

Go to the Powertrain On Board Diagnostic (OBD) System Check

1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found, correct the condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

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Go to Step 16

Go to Step 3

Was visual/physical check performed?

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Go to Step 4

Go to Visual/Physical Checks

1. Remove and check air filter element for dirt, or for being restricted. Refer to Air Induction System .
2. Replace air filter element if necessary. Refer to Air Cleaner Element .

Was a repair required?

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Go to Step 16

Go to Step 5

1. Check fuel pressure. Refer to Fuel System Pressure Test .
2. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 16

Go to Step 6

1. Check for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Testing Procedure .
2. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 16

Go to Step 7

1. Using a scan tool, monitor KS system for excessive spark retard activity. Refer to Knock Sensor (KS) System .
2. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 16

Go to Step 8

1. Check for proper ignition coil output voltage with spark tester J 26792 :

-	Clip the spark tester to engine ground.

-	Connect one end of a spark plug wire to the spark tester; connect the other end of the spark plug wire to the coil being tested.

-	Connect one end of another spark plug wire to the other coil tower; connect the other end of the spark plug wire to ground.

-	Crank the engine while observing the spark tester; a crisp blue spark should be observed.

-	Repeat the above steps for each coil.

2. If adequate spark is not present at all coils, repair as necessary.

Was a problem found?

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Go to Step 16

Go to Step 9

1. Remove spark plugs, check for wet plugs, cracks, wear, improper gap, burned electrodes, or heavy deposits.

Notice: Determine the cause of the oil or gas fouled spark plugs in order to avoid damage to the new spark plugs.

1. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 16

Go to Step 10

1. Check ignition coils for cracks or carbon tracking.
2. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 16

Go to Step 11

1. Check PCM grounds for being clean, tight and in their proper locations. Refer to Engine Controls Schematics .
2. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 16

Go to Step 12

1. Check exhaust system for possible restriction:

•	Inspect exhaust system for damaged or collapsed pipes.

•	Inspect muffler for heat distress or possible internal failure.

•	Check for a possible plugged three-way catalytic converter by checking exhaust system back pressure.

•	Refer to Restricted Exhaust System Check .

2. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 16

Go to Step 13

1. Check Torque Converter Clutch (TCC) for proper operation. Refer to 4T60-E Transaxle Diagnosis.
2. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 16

Go to Step 14

1. Engine mechanical problem. Check for low compression, incorrect or worn camshaft, loose timing chain etc. Refer to Engine Mechanical.
2. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 16

Go to Step 15

1. Review all diagnostic procedures within this table.
2. When all procedures have been completed and no malfunctions are found, review/inspect the following:

•	Visual/physical inspection.

•	Scan Tool data.

•	Freeze Frame data/Failure Records Data.

•	All connections within a suspected circuit and/or system.

3. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 16

Refer to Technical Service Bulletins

Operate the vehicle to duplicate conditions present when the original symptom was noted.

Is symptom still present?

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Go to Step 3

System OK