It's the 2.4 liter. It shakes a little at idle, in drive, but mostly when it up shifts to a higher gear and the rpms drop. If i gas it when the shaking starts it will stop until it upshifts again.What engine do you have? When does it shake, in drive, in neutral while driving, certain speed?
Did they scan for error codes? It could be an issue with the torque converter in the transmission.
Not sure but there are no waning lights on the dash.