Vibrate

[Morosanu 90]

Hi, I have a problem I have a vibration in my car an audi a6 2010 le mans 2.tdi ,, I was with her at the mechanic they put on the computer they checked the injectors but nothing .. the car works very well does not make noise I have no sensor  lit, no smoke, just a simple vibration I can't find out.  those with her .I specify that I only have the vibration when I stand still while walking, nothing is felt, nothing is heard.

[Steve Q]

Could it be an engine mount or gearbox mount?