94 sunbird speedometer stops working

I just purchased a 1994 sunbird LE (as basic as can be) I have a problem with the speedometer. It will only work 75% of the time the rest of the time it does nothing.. Like it has a broken cable. Does anyone know what I have to do to repair it?:shakehead

Check the VSS sensor connection, should be above the passenger's side drive axle, it may be loose or damaged...... could also be a bad VSS sensor, or bad ECM....