GM Service Manual Online
For 1990-2009 cars only

Restricted Exhaust Pontiac/Buick

Step

Action

Values

Yes

No

1

Check for any kinked exhaust pipes.

Are there any kinked exhaust pipes?

--

Go to Step 2

Go to Step 3

2

Repair or replace the exhaust pipes as necessary.

Is there still excess back pressure?

--

Go to Step 3

System OK

3

Remove the muffler and visually check for restrictions.

Are there any restrictions in the muffler?

--

Go to Step 4

Go to Step 5

4

Replace the muffler. Refer to Muffler .

Is there still excess back pressure?

--

Go to Step 5

System OK

5

Check for a crimped tail pipe or an obstruction in the tail pipe.

Is the tail pipe crimped or obstructed?

--

Go to Step 6

Go to Step 7

6

Remove the obstruction or straighten the crimp in the tail pipe. If the tail pipe is damaged, replace the tail pipe assembly. Refer to Tail Pipe .

Is the exhaust system still restricted?

--

Go to Step 7

System OK

7

Check for a plugged three way catalytic converter.

Is there a plugged three way catalytic converter?

--

Go to Step 8

--

8

Refer to Restricted Exhaust System Check in Engine Controls to diagnose the cause of the restriction.

Is the exhaust system still restricted?

--

--

System OK

Restricted Exhaust Chevrolet/Oldsmobile

Step

Action

Values

Yes

No

1

Check for any kinked exhaust pipes.

Are there any kinked exhaust pipes?

--

Go to Step 2

Go to Step 3

2

Repair or replace the exhaust pipes as necessary.

Is there still excess back pressure?

--

Go to Step 3

System OK

3

Remove the muffler and visually check for restrictions.

Are there any restrictions in the muffler?

--

Go to Step 4

Go to Step 5

4

Replace the muffler. Refer to Muffler .

Is there still excess back pressure?

--

Go to Step 5

System OK

5

Check for a crimped tail pipe or an obstruction in the tail pipe.

Is the tail pipe crimped or obstructed?

--

Go to Step 6

Go to Step 7

6

Remove the obstruction or straighten the crimp in the tail pipe. If the tail pipe is damaged, replace the muffler/tail pipe assembly.

Is the exhaust system still restricted?

--

Go to Step 7

System OK

7

Check for a plugged three way catalytic converter.

Is there a plugged three way catalytic converter?

--

Go to Step 8

--

8

Refer to Restricted Exhaust System Check in Engine Controls to diagnose the cause of the restriction.

Is the exhaust system still restricted?

--

--

System OK