Random Idle issue
 

Hey People, I have a Protege 5 and recently I was having some idle issues. It only happens once in a while, but when I pull up to a light it wants to stall. If I rev the engine and hold it at about 2000 rpm its fine. The odd thing is it only does it once and while. For example my drive to work I might hit 6 red lights and it will only do this once. This is consistent with my drive home from work. Does anyone have any suggestion. I was wondering if it could be a dirty 02 sensor or a timing issue.