About 3 weeks ago, my clutch started slipping a little bit, i didnt think too much of it at the time. One time on the highway, i could only go upto 60mph...I could go faster, but i'd be red lining my engine in order to get it going. Recently, it started slipping really bad, i'd have to rev the engine to 4k RPM to get it going from a stop. I noticed however, on cold days, the clutch works great. But when i run the car for a long time, or let it sit to warm up, the clutch is gone. One time, i was just messing around, to see if the temperature had anything to do with it, i surrounded the clutch master cylender and resevoir with snow, and it helped a lot, it didnt slip for a few days, until it all melted because I left the car in my garage. Later, i let my car run while I was in my friends house for about 10 minutes, we came out, put it in reverse, and let the clutch up...all the car did was sat and revved while I was giving it gas. We popped the hood, and let the car sit for about 45 minutes, and the clutch worked...but slipped pretty bad. I just replaced the slave cylender about 3,000 miles ago. I made sure to bleed the lines really good. So is it my clutch or master cylender going out? I still have nice pressure when i press the clutch pedal down..it's just the clutch isnt "gripping" sometimes when I let it up. I noticed it only does that on warm days, or if the engine has been running for a while. I bought the car used, and I'm not sure when the clutch has been replaced last...and I dont really have $250 for a new clutch...so im just hoping its the master cylender. There is 168,000 on the chassis, and about 80,000 on the engine. Oh yea, when the clutch isn't "gripping" i can come to a complete stop in 1st gear w/o the car stauling, and in order for me to get goin, i let the clutch pedal up all the way, and i just have to rev the engine up high before it starts to catch and get going...I dont know if that helps.