I just replaced the clutch in my car, everything went fine, after about 50km it started stalling a lot, mostly when its up to temp. If i push the clutch in when i stop it stalls, at this point i bump start it and it runs great until i go to stop again. When its up to temp unless i tap the gas pedal when it starts itll stall. On the first test drive it threw p0300-p0304 (missfire all 4 cylinders) cleared the codes and 200 km later no codes have came up. Im really stumped any help would be awesome!
Your description reminds me of a blown brake booster diaphragm - when you hit the brake, the vacuum booster lets a bunch of extra air into the intake manifold and the engine leans out and stalls. Try clamping off the power brake booster and retest. (of course be aware that it will be harder to work the brake) See if you can find a test for the brake booster in the manual...
Definitely sounds vacuum related. Since you have to take the air box out of the way to replace the clutch, I would check there. I would also look at the vacuum line running to the brake booster, since you have to reach back around that to the shifter cables.