I have a 2013 SE Hybrid with the same kind of issue - sounds almost like a ping pong ball is bouncing around inside the wheel well. I did not notice it on the test drive and my wife was really against me buying this vehicle so now she is riding me hard to get it fixed - same out come as noted above - Rancho Santa Margarita Ford in Orange County said they did fix one with this problem but Ford has since told them NOT to repair any further vehicles until a "permanent solution" is found. I find this totally unacceptable and am considering pursuing lemon law type action as it is not acceptable for a brand new car to behave this way. If Ford knows about it and has no answer, there should be compensation of some kind. I was financed through Ford Motor Credit and feel like giving it back to them (I know, can't do it but sure want to!) I am also only averaging 39 miles to the gallon but that is still better than most cars. I was also told that if you put it in cruise at 62 you could get up to 100mpg. I just finished a road trip trying to use that technique as much as humanly possible and only got the mpg to 40. I get raves from the looks but as soon as someone goes for a ride with me they always ask, what is that noise?
