usually a sway bar link is the culperate....sometimes the spring insilators are broken also....look at the tips of the front spring....at each tip in between the leaves should be a white (when it was new anyways..) piece of plastic that sits in between them.....they wear out and break off and sometimes you will hear a spring slap when turning hard or over big bumps.....ford sells a repair kit that is pretty easy to install but it takes two guys and watch you dont crush a finger......Marc