Engine performance

When my engine gets up to operating temperature and I stop at a light, sometimes the idle lopes and stalls, I can start it back up and it may idle rough, if I drive for more than 9 miles or so after it's up to operating temp and shut it off, the coolant tank bubbles, if I put it in neutral when I am at a red light, the idle goes up a bit, then lopes down, also, it also lacks power on acceleration and there is no check engine light on, the temp gauge appears to be working fine and my a/c is still very cold, when the engine is cold, all symtoms are gone.