What would cause a humming sound in a 99 park avenue it sounds kind of like a propeller and it goes with the engine it gets louder when you accelerate and you can't hear it at all when slowed to 15mph?
A humming noise on a 1999 Park Avenue is caused by bad wheel bearings. When bearings are loose or worn they will create a loud humming noise that will get louder and louder as the car accelerates.
