Just a "me too" post. I have this same passenger seat rattle. First I thought it was the headrest, then I thought it was thr HVAC vent under the seat, but no, it is the seat back itself. I was at the dealer just today for this and they were unable to reproduce or diagnose it. :banghead:
Sent from my Galaxy Note 2 using FF Mobile.
MK3 Focus = a lot of good ideas rather poorly executed.