I own a 1996 Firebird Formual 6 speed. When I just rest my foot on the clutch without applying any pressure, the pedal goes down. Even though it is all the way down it will not go into gear. When I am driving it slowly releases itself when I mash the clutch pedal all the way down, therefore I can not leave the clutch out without braking to stay even on a hill. It changes gears fine if I do it before it completely releases itself. What could be the problem and what should I do? Faulty slave/clutch master cylinder?