I've got a 93 Cobra with stock clutch/tranny/shifter.
When the clutch is engaged (my foot is completely off the clutch, correct me if I'm wrong) there is a loud clicking noise and a strong vibration in the clutch pedal, doesn't really matter what gear I am in, but you can hear it best when it's just idling in neutral.
If i push the clutch in, clicking goes away, and the vibration goes away.

At first I would only hear it when the car was warmed up, but it's gotten progressively worse, the more I drive it, and now it's pretty much constant (unless I'm pushing the clutch), so I'm getting worried.

Has anyone else experienced this? If so, do I just need to do some adjusting, or is my clutch going? I should mention, otherwise, the car shifts great, although sometimes I have issues getting it into reverse, but every fox body I've had has had that issue.

 

Not sure why the pedal would vibrate. If the noise is present while your foot is off the clutch I would suspect something in the tranny, such as input bearing or counter shaft bearings since those turn in every gear, even neutral, with the clutch engaged (foot off pedal).

 

most likely it's the throw out bearing, pull the tranny and bell housing