Exhaust vibration

[jpfisher]

2014 A6 3.0T. Noticed this new sound lately on cold starts and during downshifts while coming to a stop. While looking under the car and keeping rpm at 1200, i can see the exhaust vibrating pretty bad. Anyone have an idea of what is causing the vibration to occur?


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[got_boost]

I would be looking at the eng mounts. Usually it's the pass side that is the first to go but I'd check both.

[Valpo A7]

Everyone wants to blame stuff on engine mounts. My mounts have 2,500 miles on them and the downpipes shake as well.

What it is I am not sure why or even if it was like that before I changed my mounts.

[bahula03]

Agree with Valpo. ~1200rpm seems to be a resonant frequency for the motor, the same thing will happen if you cold start the car as it settles from the initial cold idle to warm idle. While failing/failed engine mounts or exhaust flex joints can exacerbate the symptoms, it's just a thing that happens. Unfortunately that won't help you un-hear it [facepalm]

[Valpo A7]

My flex pipes rattle as well. When I had them out for engine work I was able to inspect them and it seems there is some material that flaked out of the resonator and was rattling around in the shell.

[f4m0u5]

i had this eaxact problem. Replacing engine mounts helped, but the real problem was the flex joints. Having new ones welded in took care of the rattle and vibration around that rpm range stating still and during de- accel

[bozack]

i know after aan oil change i got a sound like this from that shield around the exhaust under the front seats