The 2012 MKZ we just purchased is great in many ways. When talking on the cell phone through the vehicle's system, the person at the other end hears a high level of background noise when the car is moving. No noise is heard when the car is standing still. What can be done, either through noise reduction or equipment upgrade to make this better? This is a fantastic car with only 16,000 miles, so I intend to hang on to it for a while. Thanks.