The failure of the passenger side motor mount is common on 2000-2004 foci. My 2005 was vibrating a lot at idle, so I decided to check my mount. I used the engine hoist to take the motor weight off of the mount, and sure enough all of the vibrations in the cabin disappeared. I'm not sure if that test proves conclusively that the mount is bad, but in my case the mount was the problem. I assume this mount is original, and it lasted 65000 miles. Be safe when working on cars. Before starting this job, you should probably set the parking brake and disconnect the negative battery cable. Follow this video at your own risk.
ford focus, motor mount, car vibration, instructional video, how-to, tanman, 758