After owning my Sport for a couple of weeks, I began to notice a buzzy rattle sound in the interior while going over rough road surfaces. I have to admit that squeaks and rattles in cars drive me absolutely nuts, to the point of ruining the whole experience. At first it seemed like the sound was coming from the rear of the interior, but after some trial and error I was able to locate the source of the rattle which was just behind the sunroof opening. If I press my hand against the headliner just behind the sunroof, the sound goes away. I also noticed that closing the sunroof cover greatly reduced the rattle, but I can still hear it now and then even with the cover closed. I'm not going to go messing around with the headliner as I see a high probability of me screwing it up, but I am going to have the dealer look into this next time I'm in for service. I did some looking around online and it appears that the 2013+ Fusions have had a fair amount of headliner issues, so I don't know if this is a version of the same thing. Once I have it looked at I will follow up here in case this issue crops up with anyone else. It's really too bad since otherwise this car is impressively solid and rattle free on the poor road surfaces of Maine.