Or bounces I have a 3 way clutch cable

 

does it bounce while your just sitting there idling? I don't completely understand whats going on. Can you give a little more detail

 

Yes at idle but even more while I drive under a light load on it but less when I give more gas or load on it ??

 

My 03 Mach 1 did the same after replacing clutch and pressure plate. I looked at several other forums and found this to be a common problem. My clutch pedal vibration was resolved with a different pressure plate. Others have corrected by installing a new quadrant and manual adjuster. The wratchet self adjusting quadrant that is stock does not always maintain clearance between the throwout bearing and pressure plate diaphram. Any variation in the diaphram fingers will cause the pressure plate to tap the throwout bearing which will transfer the pulsing through the clutch pedal. Mine was most noticable between 1,500 and 2,500 rpm.

Try pulling the pedal up with your foot to see if the vibration goes away. That can stop the vibration by creating extra clearance between the throwout bearing and pressure plate. A manual adjuster is the best bet, as a new pressure plate could result with the same problem. Good luck.