Have you tried using the steering wheel button on the bottom right side to reconnect? Mine sometimes disconnects or when I leave the car running or warming up and leave the car and I go far enough away that the Bluetooth disconnects.
Sorry you had a bad experience with your steering rack R2D2! I can almost guaranty you the problem was not caused from sitting on the lot for 4 months if it occurred 3 years later. Just poorly manufactured parts IMO. Many years ago there was nylon used in most tires and that caused flat spotting from sitting but it rarely happens today. Happy Motoring! :)
Chuck your problem is most likely the rear driveshaft. Was a big issue on earlier 2007-2012 MKZ's and the dealers were replacing them under warranty and even out of warranty. Your car should ride smooth as silk with no vibrations. The dealer is telling you otherwise since they cant find or dont want to fix the problem. I would check the rear driveshaft!!
I feel in any worthwhile car you should use full synthetic. Why not use the best oil available especially in the northeast where we operate our cars in sub zero weather and in extreme heat.
I work in the auto parts industry and this figure was told to me by an oil manufacturers rep. It is just a minimum requirement and I would assume there is a higher percent than that.