I bought a 2002 Audi A4 b6 avant and it has a problem with the clutch pedal, it's very difficult to get it in gear when the engine is cold, you have to put it in gear before you start the engine then when changing gears it's like changing gear without depressing the clutch pedal, the pedal is more than half way to the floor as if the return spring has broken, when stationary in gear it slightly creeps forward, and the clutch is biting right off the floor, it seems like the slave rod needs extending to get more clearance, now here's the really weird bit, when the engine has warmed up the problem is not so bad it seems like there is more clearance, I've got a lot of experience working on cars over the years but never came across something like this

 by the way this is a 1.9 TDI pd engined car

Sounds like a problem with the clutch to me? How many miles has the car done and has it ever been changed?

The cars done 145000 miles, I have no idea if it's ever had a new clutch, as the problem is not consistent I was thinking more on the master or slave cylinder, I would have thought any problems with the clutch would be consistent 

Would anyone know if the clutch pedal assembly for an Audi s4 2002 would fit a 2002 a4 1.9 TDI as I'm thinking of taking it out and changing some parts

Not sure on the S4 parts, I'd have thought not in my opinion but I could be wrong. I'd imagine a clutch kit would include the slave cylinder though.