I doubt a mount would be bad at that mileage. We see very few mount problems anymore on late models.

It sounds to me like a misfire event. Tell them to run a smoothness test (and print it) and if they say its OK verify the running against a new one in their stock.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician