Questions and Answers
Audi Exhaust Noise
Q. 1997 Audi A4, 2.8 12 valve, automatic transmission, automatic, 65,000 miles. I have a problem with exhaust for about a year... Last year I have replace spark plugs and Air filter to K&N. Everything was fine for about 4-5 months then one day when drive and accelerating I heard in 2,500 to 3,500 rpm sound like there was hole in pipe and air was coming almost like a rasping noise.
I have replaced catalytic converter under warranty because was noisy but only one the other was fine, the noise was still there, Just recently I replaced cat-back exhaust resonator with muffler the noise is still there, it sounds like is coming from muffler or underneath the car but it was checked by the guys who installed cat-back they told me that this can be hear when under load I accelerate and air is trapped in pipe and sort of gives this sound. But I wasn't convince much about that, there are no leaks nothing at all, I have just replace spark plugs as well the noise is still there.
Thanks,
PaulA. I would check the valve adjustment. You may have some tight exhaust valves and are hearing combustion noise in the exhaust. Also, the other cat may be partially clogged causing the noise.
If you put on an aftermarket exhaust system, then it is a good possibility that is the source of the noise. I have found that most aftermarket exhaust components, while perfectly good, sometimes are not as good as an OEM exhaust system.
Additional Information provided courtesy of ALLDATA
