What is wrong with my clutch pedal?

[Squozen]

Hi all,

I recently purchased a 2003 Boxster S with about 34000 kms on the clock (that's 21000 for you weird imperial types).

When I press the clutch pedal in it moves smoothly, but when I release it, it feels a bit rough and 'grabby'.

Any ideas what it could be? I am hoping it just needs the cylinders bled, or perhaps the master/slave cylinders have broken a seal... but I'm completely talking out of my arse.

I'm presuming it isn't an issue with the clutch/pressure plate given the low mileage, but I have no idea how the previous two owners drove it.

Any advice would be gratefully received!