idle and timing

Alright, so im having an issue with my idle. When the car is still warm and i start it the idle bounces around a lot. Almost to the point of dying. I have to wait about a minute for it to even itself out and then its completely fine until i shut it off and start it when its already warm again. Ive been playing with my timing lately and wondering if that is a possible cause. If not, what is? Also i was wondering if anybody could recomend plug gap to me. it the gt40x crate engine, E303 cam aluminum gt40 heads, 30lb injectors and i run about 34lbs of fuel pressure. i appreaciate it.