Why is the ford focus making a rattling noise while idle?

One of the most common reasons that Your Ford Focus will make a rattling noise while it is idling is if there is a problem with the engine. Usually this can be caused by bad valve springs in the engine that will make excessive noise while the vehicle is sitting still. Rattling noises while You are stopped can also be caused by worn out motor mounts. These will lead to vibrations transferring throughout the vehicle and can make noise by shaking components in Your car. The last reason You may get a rattle noise is just loose components. If Your bumper is loose, or any interior panels are loose they may vibrate and make noise just while the vehicle is running. There may be nothing mechanically wrong, it can just be some things that just need to be clipped back into place.