I've had a slight rattle for a while on my 2010, but today I finally diagnosed and fixed it. The annoying sound came from the the air shock on the right side of the lower glove box, which you just barely see with the box open. After lowering the panel above the footwell (one hook and three clips), and then laying down awkwardly, on your back, in the footwell...you can get a better look. The shock is quite wiggly, but has a convenient eyelet on the top of it, so I fashioned a small bungee and hooked it as shown in the picture. If you need to do this fix, I hope you have small hands and good contortion skills!