I Just recently got this issue. The clutch pedal vibrates engaging the pedal in about 1" or so. Vibrates bad, like bounces on your foot when rested on it, foot massage. As you continue to push it in more it goes away. Also when the pedal is vibrating there is a noticable noise in the cabin of the car and more in the engine bay. Sounds like a knocking noise and goes away when clutch engaged. I have seen many searches on this topic. But i havent seen a solution at all! I have already replaced the flywheel with a light weight flywheel thinking that was it and still have the same problem. The car is apart right now for the second time. The whole clutch assembly seems to be perfectly fine looking at it on the lift. I ordered a clutch and pressure plate today but not even sure thats going to fix it. I need a soultion or help asap!!!

 

It sounds like a bad TOB to me.