I'm experiencing a thumping noise when I get off the gas and coast. I hear it mostly over 40mph. When I get back on the throttle the noise gets quiet or goes away completely. Sounds like "duh duh duh duh". Again, only when I'm off the throttle and coasting. Tires are couple weeks old, and I've had the shop recheck the balance. Shop drove it and couldn't find any obvious problem. It's a 2009 328xi wagon.


Any ideas of what I should look into?