I bought my truck with 170k on it and at 174k I pulled out a luk single and solid flywheel and went with a ky clutch single. Ever since I can remember the clutch pedal has felt "spongey" at the top. On cold mornings or if the truck sits for a few days the pedal will sink about halfway down and ill have to pull it up with my toe. Even after a full day of driving I can always pull the pedal up with my toe about half an inch. On other ZF6's i've driven, the clutch pedals stay all the way up all the time? I've bled the master cylinder and even replaced it. any ideas?