DEFINITION: Engine power variation under steady throttle or cruise. Feels like the vehicle speeds up and slows down with no change in the accelerator pedal.

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 22

Go to Step 3

Was visual/physical check performed?

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Go to Step 4

Go to Visual/Physical Checks .

Be sure driver understands Transaxle torque converter clutch and A/C compressor operation as explained in the owner's manual Inform customer how TCC and the A/C clutch operates

Is the customer experiencing a normal condition?

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System OK

Go to Step 5

1. Start the engine.
2. Observe the HO2S 1 voltage display on the scan tool while modulating the throttle.
3. If the HO2S 1 voltage does not respond quickly to changes in throttle position, check for a contaminated HO2S.

Was a problem found?

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Go to Step 22

Go to Step 6

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 22

Go to Step 7

Monitor Long Term Fuel Trim on the scan tool.

Is Long Term Fuel Trim significantly in the negative range (Rich condition)?

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Go to Step 8

Go to Step 9

1. Check items that can cause the engine to run rich. Refer to Diagnostic Aids in DTC P0172 Fuel Trim System Rich .
2. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 10

Go to Step 22

1. Check items that can cause the engine to run lean. Refer to Diagnostic Aids in DTC P0171 Fuel Trim System Lean .
2. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 10

Go to Step 22

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

-	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.

1. If adequate spark is not present at all coils, replace coil(s) as necessary. Go to Ignition Control Module Replacement .

Was a problem found?

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Go to Step 22

Go to Step 11

1. Check for loose ignition control module ground. Refer to Ground Distribution in Electrical Diagnosis.
2. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 22

Go to Step 12

1. Visually/Physically inspect secondary ignition wires. Check for the following conditions:

•	Check all ignition wire resistances; should be less than the specified value.

•	Ignition wires for cross firing.

•	Ignition wires arcing to ground.

•	Ignition wires for improper routing.

Important:: Spraying the secondary ignition wires with a light mist of water may help locate an intermittent problem Ignition components will arc to ground when a secondary component is faulty.

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

Was a problem found?

30,000 ohms (30K ohms)

Go to Step 22

Go to Step 13

1. Inspect the ignition coils for cracks or carbon tracking.
2. If a problem is found, replace coil(s) as necessary. Go to Ignition Control Module Replacement .

Was a problem found?

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Go to Step 22

Go to Step 14

1. Check ignition coil secondary resistance.
2. Replace any coil(s) which are not within the specified resistance values. Go to Ignition Control Module Replacement .

Was a problem found?

5000 - 8000 ohms (5K-8K ohms)

Go to Step 22

Go to Step 15

1. Remove the spark plugs.
2. Check for wet plugs, cracks, wear, improper gap, burned electrodes, or heavy deposits.
3. If a problem is found, repair as necessary.

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

Was a problem found?

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Go to Step 22

Go to Step 16

1. Check the injector connections.
2. If any of the injector connectors are connected to an incorrect cylinder, correct as necessary.

Was a problem found?

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Go to Step 22

Go to Step 17

1. Check PCM grounds for being clean, tight and in the proper locations. Refer to Ground Distribution in Electrical Diagnosis.
2. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 22

Go to Step 18

1. Check MAF sensor connections.
2. If a problem is found, replace faulty terminals as necessary. Refer to Wiring Repair in Electrical Diagnosis.

Was a problem found?

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Go to Step 22

Go to Step 19

1. Visually/physically check vacuum hoses for splits, kinks, and proper connections and routing as shown on the Vehicle Emission Control Information label. Refer to Emission Hose Routing Diagram .
2. If a problem is found, repair as necessary.

Was a problem found?

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Go to Step 22

Go to Step 20

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. Go to Restricted Exhaust System Check .

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

Was a problem found?

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Go to Step 22

Go to Step 21

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

•	Visual/physical inspection. Go to Visual/Physical Checks .

•	Scan tool data. Go to Engine Scan Tool Data List .

•	Freeze Frame data/Failure Records data.

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

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

Was a problem found?

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Go to Step 22

Review technical 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