clutch slave cylinder

This is most likely a master cylinder problem as opposed to a slave cylinder issue.

I had the same symptons as you describe and replaced my clutch master. See here: http://members.tripod.com/AZPOCA/index9e.html

Instead of an aftermarket unit, I just went with a stock unit so I wouldn't have to mess with the fittings. Replacement is a pain in the a$$ but it's a very straightforward bolt-off:bolt-on procedure.

I am starting to have the same problem you are, but not as bad yet.

I had the chance to visit Jerry at PI Motorsports last week and he was kind enough to show me what was happening on a part outside the car. Dave and Jerry are great guys over at PI Motorsports in California. It was my first time at their shop and I am glad I took the time to stop by and see them.

Inside the Master cylinder there are 2 rubber O rings, these may be your problem. They are not holding the pressure anymore. To change these as Jerry explained is much easier that changing out the entire cylinder and worth a try first. He has the O rings.

If this doesn't fix the problem, then the problem is the cylinder itself, condensation has collected at the bottom of the cylinder and casued pitting in this area. Becasue of this the O rings are not sealing and holding the pressure.

I will be changing my O rings later on this week. If this doesn't work, then I will change out the whole cylinder.

PI has them, the whole cylinder unit, polished and very nice for under 100.00.