Inspect the exhaust tubing.

Is the exhaust tubing kinked?

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Go to Step 2

Go To Step 3

If possible, repair the damaged exhaust tubing. Otherwise, replace the exhaust tubing.

Is the exhaust system restricted?

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Go to Step 3

System OK

Inspect the muffler.

Is the muffler restricted?

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Go to Step 4

Go to Step 5

1. If a restriction is likely, remove the muffler and visually inspect it.
2. If the damage to the muffler is not repairable, replace the muffler. Refer to Muffler Replacement .
3. Correct the engine malfunction.

•	For the 4.3L engine, refer to Diagnostic Starting Point .

•	For the 5.0L/5.7L, refer to Diagnostic Starting Point .

•	For the 6.5L engine, refer to Diagnostic Starting Point .

•	For the 7.4L, refer to Diagnostic Starting Point .

Is the exhaust system restricted?

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Go to Step 5

System OK

Inspect the end of the tailpipe.

Is the end of the tailpipe obstructed?

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Go to Step 6

Go to Step 7

Remove the obstruction, or if the end of the tailpipe is crimped, straighten the outlet. If the tailpipe can not be repaired, replace the tailpipe. Refer to Tail Pipe Replacement .

Is the exhaust system restricted?

--

Go to Step 7

System OK

Inspect the catalytic converter for obstructions, which may have occurred as a result of a serious engine malfunction.

Is the catalytic converter obstructed?

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Go to Step 8

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1. Replace the catalytic converter. Refer to Catalytic Converter Replacement .
2. Correct the engine malfunction.

•	For the 4.3L engine, refer to Diagnostic Starting Point .

•	For the 5.0L/5.7L, refer to Diagnostic Starting Point .

•	For the 6.5L engine, refer to Diagnostic Starting Point .

•	For the 7.4L, refer to Diagnostic Starting Point .

Has the repair been completed?

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System OK

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