Normal engine noise or is it muffler problem?

I have a 2001 Pontiac Grand Am SE 4 Cyl FWD with 211,000 miles. When I accelerate, the car makes a loud roaring noise. I’m not sure if it is normal engine noise or is it exhaust system problem?

When I step on the gas pedal, I hear a loud, continuous roaring noise. When I take my foot off the pedal, the noise goes away. The car is still moving but I’m not pressing on the gas pedal. As soon as I step on the gas pedal again and push down harder and harder to accelerate, it makes the same noise again. I don’t know if this is normal engine noise for an old car or not.

I went to a muffler shop and they said there’s no exhaust leak and my catalytic converter and muffler are good. But this is a 23 year old car and I don’t think the muffler has ever been replaced. How long does a muffler last on a car? The exhaust tail pipe tips look very old and rusted. Do I have to replace parts like muffler and tail pipe tips after certain miles or do they last forever?

All he did was lift my car up to look under the car. He didn’t take the car out for a test drive. Can you check a muffler simply by looking at it? I don’t think he took it off to look inside the muffler. I’m considering going to another muffler shop to get a second opinion.

What you are describing is an exhaust leak. Sometimes these occur at the joints and are undetectable unless you have the engine running - and I’ll bet the muffler shop didn’t do that - shame on them. They missed an opportunity to make some money.

On the other hand, exhaust systems get rusted very badly and taking things apart to fix a leak at a joint is a lot of trouble and expense. It might be easier to replace the whole system.

Take the car somewhere else.


Can you use a smoke test to find where it is leaking, if it is leaking at all?

They told me there’s no leak and my catalytic converter and muffler are good. But this is a 23 year old car so I assume some parts under the car are very old and rusted and have never been replaced. Can a muffler still work pretty good after 23 years? or should I consider replacing it anyway? The two tail pipe tips look very old, rusted and burned. Should I consider replacing them too or they don’t matter if they are new or old.

Mufflers don’t wear out, rust makes holes in them. Same for the rest of the system…except… the flex joint right behind the engine. It can fail with little outward appearance. @CapriRacer is right… if the system wasn’t checked with the engine running it would not be apparent. A smoke test is not required, a less lazy exhaust tech is.


What about the exhaust manifold? You didn’t mention that.

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You have a rusty connection.
Your resonator is rusted out.
Your muffler is rusted out internally.
All of the above?

Do I really need to be the one to say this?
Are you seriously saying you don’t know the difference between what your car sounds like normally, and when there is something wrong?
Please just stop driving!
Am I the only one thinking this?


If he had a 2001 Corolla ya wouldn’t hear a peep out of him.

First thing I thought of was a torque converter problem, slipping or coming apart. A test drive by a mechanic should be able to identify the noise.

Perhaps he misunderstood the purpose of your visit. You wanted to solve a noise problem; someone would need to drive the vehicle to determine the cause of the noise. Did you ask only to inspect the muffler?

There is no reason to look inside the muffler, but if I remove the muffler for you to inspect the inside, the charge will be $350 for the new muffler and you can keep the old one.

Perhaps the noise is from the supercharger that was installed by the previous owner, isn’t this the 4-cylinder Pontiac that has out of control wheel spin while accelerating? Are these problems exaggerated?

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If I had that problem, being a diy’er, my first step would be to listen along the entire exhaust system using a length of garden hose as a stethoscope while an assistant periodically bursts the rpm, avoid breathing exhaust fumes.; my second step would be to use a timing light to double-check the ignition timing is behaving as expected.

A vacuum leak could cause a noise to except you’d probably get some rough running.