I have a 2014 Fusion Energi Titanium that I bought in August and I also have been having the rattling issue. Mine seems to come from the drivers side rear part of the car. I took it in once and they secured the rocker panels which didn't do anything. The second time they replaced something(I'm not sure what at the moment, but i'll update when I find my paperwork). That seemed to work for a couple weeks, but now the rattle is back. Not as loud as before, but is definitely there. Very frustrating.