I just bought a 2003 A6 2.7T 6-speed with 95,000 miles. When it is started cold and you are driving, say 30 mph or faster, there seems to be some surging. Under hard acceleration this does not seem to happen. I was wondering if it could be due to the previous owner using regular fuel? Also, third gear seems to be a little hard to go into at times. Any thoughts? Thanks.

 

Have you change the transmission oil? I would start there and check if there are any metal debris on the magnet of the drain plug.

 

describe hard... like an extra push... or it grinds for a second before going in...?

and does it flash the check engine light when it surges...?