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 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.

Did you find a bulletin that addresses the symptom?

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Go to Step 13

Go to Step 3

Did you perform a thorough visual and physical check?

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Go to Step 4

Go to Symptoms

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 13

Go to Step 5

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

Did you find a problem?

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Go to Step 13

Go to Step 6

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.

Did you find a problem?

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Go to Step 13

Go to Step 7

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

Did you find a problem?

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Go to Step 14

Go to Step 9

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 11

Go to Step 13

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 12

Go to Step 13

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 11

Go to Step 13

1. Check for the following engine mechanical concerns:

•	A low compression

•	Any sticking valves

•	A hydraulic valve lifter problem

•	A leaking cylinder head gasket

•	A worn or incorrect camshaft

•	An incorrect cam timing

•	A damaged timing belt

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

Did you find a problem?

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Go to Step 13

Go to Step 12

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 or inspect the following:

•	Review the scan tool data

•	Review the Freeze Frame data

•	Inspect all of the electrical connections within the suspected circuit or system

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

Did you find a problem?

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Go to Step 13

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

Go to Step 14

Are any other driveability symptoms still present?

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Go to Symptoms

System OK