Got a 06 McsA that makes a "whirring" sound when in motion. Quiet when I stop It is louder when you're running beside another car or alondside a wall or divider. Imagine a "small" plastic bag stuck under the car that would be the sound. I checked and nothing is there. The sound doesnt speed up with the car. Its constant, just louder when faster. I eliminated the cv's since it does not vary. Oh and the right engine mount need to be replaced tomorrow. Any ideas from the great minds of NAM?