I've just got off the phone with my local Ford dealer and was told that my exhaust was installed wrong and the rattle I'm hearing is from the rear o2 sensors rattling on the trans crossmember. Now my exhaust hasn't been touched in a over a year and the rattle noise I'm hearing is coming from under the rear seat far away from those sensors. Could the sensors really be making this noise? I've noticed that my x pipe which is a BBK is upside down