New 22 with 200 miles on it. When the vehicle is running in park or in gear, there is a really faint harmonic like hum that changes pitch, up and then down and repeats every few seconds. I mean really faint. The radio and road noise cover it up and it does not appear related to AC from what I can tell as it still does it with the AC off. My wife hears it, so it's not in my head... Any thoughts?