Definition: The vehicle has an excessive rotten egg smell. (Excessive odors do not necessarily indicate excessive emissions.)

Did you perform the On-Board Diagnostic (OBD) System Check?

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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 present, correct the condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

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Go to Step 17

Go to Step 3

Did you perform a thorough visual/physical check?

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Go to Step 4

Go to Symptoms for the Visual /Physical Check

1. Check for any vacuum leaks in the following areas:

•	The vacuum lines

•	The intake manifold

•	The throttle body

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

Did you locate any vacuum leaks?

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Go to Step 17

Go to Step 5

1. Check the fuel cap for a proper installation.
2. Secure the fuel cap if necessary.

Was the fuel cap installed properly?

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Go to Step 6

Go to Step 17

1. Check the fuel pressure. Perform Fuel System Diagnosis .
2. If a problem is present, repair as necessary.

Was a problem found?

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Go to Step17

Go to Step 7

1. Check for a malfunctioning, plugged, or incorrectly installed crankcase ventilation valve. Also, check the crankcase ventilation system for any plugging.
2. If a problem is present, repair as necessary.

Was a problem found?

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Go to Step 17

Go to Step 8

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 17

Go to Step 9

1. Perform Fuel Injector Solenoid Coil Test .
2. If a problem is present, repair as necessary.

Was a problem found?

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Go to Step 17

Go to Step 10

1. Refer to Engine Cooling for cooling system diagnosis.
2. If a problem is present, repair as necessary.

Was a problem found?

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Go to Step 17

Go to Step 11

1. Check the EVAP canister for fuel loading.
2. If a problem is present, repair as necessary.

Was a problem found?

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Go to Step 17

Go to Step 12

Remove any excessive carbon buildup with a top engine cleaner. Refer to the instructions on top of the engine cleaner can.

Is the exhaust odor still present?

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Go to Step 13

Go to Step 17

Check the items that can cause the engine to run rich. Make any of the necessary repairs.

Is the exhaust odor still present?

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Go to Step 14

Go to Step 17

Check the items that can cause the engine to run lean. Make any necessary repairs.

Is the exhaust odor still present?

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Go to Step 15

Go to Step 17

1. Check for the following Engine Mechanical problems.Refer to Engine Mechanical:

•	Low compression

•	Sticking valves

•	A hydraulic valve lifter problem

•	Leaking cylinder head gaskets

•	A worn or incorrect camshaft

•	Incorrect cam timing

•	A damaged timing belt

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

Was a problem found?

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Go to Step 17

Go to Step 16

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

•	The scan tool data

•	The Freeze Frame data

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

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

Was a problem found?

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Go to Step 17

Go to Step 3

Operate the vehicle under the same conditions (as closely as possible) as when the original symptom occurred.

Is the original symptom still present?

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Go to Step 3

The repair is complete. If another driveability symptom exists, refer to Symptoms .