Mary Pozzi that is...
You might want to check and see if your clutch fluid is contaminated with clutch dust.
It seems
"GM cars with manual transmissions and the LS1, LS2, LS6, and LS7 engines sometimes fall prey to clutch pedal issues during or following high-rpm shifts". Clutch dust may be the culprit.
I haven't seen this topic posted on Lat-G so I thought I'd bring it up. I recently cleaned my fluid as it was loaded with clutch dust.
Here's an excellent link:
http://www.rangeracceleration.com/Clutch_Care.html