I am currently having this EXACT SAME ISSUE. Clutch pedal goes to the floor, have to rev up to like 4500rpms, tranny will then engage, barely lift foot, car takes off. When this first happened, I replaced the slave cylinder and removed the restricer plate, thinking if I put more fluid to the slave cylinder, it'll react faster, therefore raising my engagement point off the floor. No dice. I blead and blead and blead the system, still nothing. I checked the clutch master cylinder, no leaks are visible. It COULD be leaking internally since my clutch used to engage right about 1/2 way but over time the engagement point went to the floor. My clutch is a SPEC Stage 3 and I'm thinking of just replacing it and the TOB and PRAYING that fixes the issue.

If anyone does get this figured out, PLEASE PLEASE PLEASE, let me know ASAP as I NEED to get my car back on the road ASAP.

96 Indy Red Dodge Avenger I4 5spd
225.7whp/227.2wtq @ 10psi, currently running 12-14psi.
HRC Stage III turbo setup
JE 8.8:1 pistons
Eagle rods
block bored .020" over
GReddy FMIC w/ custom piping
1G crushed BOV
SPEC Stage 3 clutch
2.5" DP, 2.5" high flow cat, 3" ERT catback w/ Magnaflow muffler and 3" tip.
much much more...