i know there have been previous postings complaining about noise from the headliner, however, no one seems to have presented a solution 'cept for having the dealer re-glue the damn thing... That brought about other issues like the dealer not re-attaching the headliner properly or glue marks, etc.
I've had my focus for a year and a half and never had headliner noise issues til two weeks ago.. Maybe it took that long for the glue to 'unstick'. I don't know. It didn't rattle or make any big noise but sort of hummed or buzzed over certain surfaces (on a smooth road it made no noise) Of course, the buzzing was mostly on the driver's side right over my ear... Grrrr! Very annoying!
In any case i was loathe to bring it to the dealer, not have the car for a day or more and risk having my pristine headliner messed up. So, i took matters into my own hands.
I got some 1/2 inch foam weatherstripping from the hardware store, the kind that's sticky on one side and has the peel off tape on the other side. i cut 4 or 5 pieces , ea. about 3 inches long, and inserted them between the black plastic surround that the headliner is attached to (I have a sunroof so it's easy to get to ) and the headliner itself. I placed one on each side and two in front and no more noises.... zero.
Those having these issues may wish to try this.. It took all of 5 minutes and worked very well. And... if, for some reason, it doesn't work for u, needle nosed pliers can be used to remove the weatherstripping....Also,, it doesn't interfere at all w/ either the operation of the sunroof glass nor the sliding shade. good luck.