Do all the cayennes sound kinda loud when driving on the highway. When i am coasting about 65 - 70 I can hear this slight humming sound and the sound changes pitch when i accelerate or decelerate, mind you this sound is very bleak. Also when I let go of the gas going 65ish the car doesnt just coast as if i were in neutral, I can feel the slight vibration in the steering wheel. I had the dealership drive it and they said its just because its an AWD with two drive shafts. Any input would be nice thanks

 

Sounds like it could be a lot of different things. Tires, wheel bearing, rear drive shaft/center bearing, or even front diff.