I have a 92 miata and put a exedy stage one organic clutch in and have had it for about 15,000 miles and for some reason if I'm in traffic or even pulling into my garage and hold the clutch pedal in for a little bit the pressure in the petal goes away and the car will stall. What's wrong? I'm not loosing or leaking any clutch fluid is it the pressure plate? Or is the clutch going out???