ive got a 96 r33 skyline gtst and when the enigne is cold its idling at around 1200 and there is no problem but once the engine heats up it starts idling at 600 and when driving and coming to a stop with the clutch pressd in the revs drop very low for example 2-300 or sometimes the car just stalls. I dont know what the problem is. Its running stock enigne with stock BOV and just 3 inch exhust system. please help