I have a sound like something is rubbing on the right rear tire at speed. It is not related to the engine - it changes with the speed of the car, not the RPM's. At 40 MPH you can hear it pretty good and the pitch gets higher as the speed increases. The tires are OK - no metal showing thru the rubber. There is nothing I can see that would be rubbing on the wheel or tire or the ground. Any ideas? Thanks in advance for your help
Frank B