Most likely your clutch pedal bushings are shot.  See http://www.mustangsteve.com/clutchbearings.html for details.  When they wear out to the point where they start popping, you may notice the pedals not sitting evenly under the dash, and the brake pedal may move when you push on the clutch pedal.  The big spring mounts can be worn also, and the spring may be binding as it travels.

You could also have some linkage problems with the Z-bar or mechanical linkage between the pedal and the bellhousing.  If your bushings are worn, it may look like the picture.

MS, Took it off and sent it to you for modification service.  The plastic bushing were worn out and the pot metal bushing were also worn and loose.