My b16 seems to want to go up and down between 250-500rpm for a few min and then stops. Sometimes longer sometimes not at all. I have changed the idle air control valve a couple times with ones from other engines and nothing, it is either worse or a little better. I am thinking it has to be the IACV but what are the odds that all of them would be bad? I don't have a fast idle anymore so this is the only thing I can think of. I have cleaned it and nothing same across the board. Any help would be GREATLY appreciated because that is the most irritating shit while you are sitting at a stoplight.