idle problem!!!

hey all.. i have a 02 audia4 diesel 130bhp.. i have a problem with the idling.. the car is idling at 1000rpm and shudders when its running which is relly annoying!! i had a diagnostics test done on the car.. the fault came up as the engine mounting solenoid valve..   would anyone know where this is located on my car...and possibly wat it looks like?? any help with this would be greatly appreciated..   kind regards   dave