i had a similar problem in my 2jz cressida, i went to drive it one day and the pedal was on the floor, found out to be 2 things, one the clutch master cylinder had a leak in it and would constantly drain the fluid, not a good thing with a cushion button hydraulic clutch, and when it ran out of fluid altogether air got into it and didnt make it work properly after fluid went back in and clutch mastercylinder was replaced, although the first clutch master cylinder melted due to the excessive heat from the turbos exhaust housing (was running an 800hp turbo (BIG)) lol and set the fluid on fire which dripped down to create a bit of a fireball under the car lol (Note: always have a heat sheild or turbo bag with your turbo!) but yeh check both of them