bernes1982

I have a 2002 A4 3.0 and the car vibrates when it's in gear and sitting still. The check engine light is on and it's giving me code PO431 (warm up catalyst below treshold bank 2) Could this cause the car to vibrate?
I was also wondering if PO431 would be a bad O2 sensor or catalyting converter?

Thans,

ezveedub

It's not the cause of the vibration in most cases, but it looks like your bank 2 cats efficiency is getting low. Usually means you'll need a new Bank 2 to catalyst. Make sure there are no leaks in the exhaust near the cat or upstream of it at the manifold, as that can also trigger this fault. If the cat is starting to come apart, it will cause running issues though.