i just swapped a jdm b20 in my 99 teg and its idleing up and down. i used the same manifold that was on my old ls. i tighened down the cold start valve and cleaned out the idle air control valve but it still idles up and down. the manifold and throttle body are tight and i let all the air outta the system. so what can be the problem? maybe the sensor on iacv?