I have a 1966 Mustang K-Code Coupe with a 4 speed transmission. The clutch pedal will not return to its full upward position when I take my foot off the pedal. I have to return the pedal to its upright position with my foot under the pedal. This problem started recently and looking inside the engine bay and under the car, I cannot see anything loose or broken. The clutch has approximately 6000 miles since it was new. Any Ideas???