Our 1999 Escort SE idles up and down at stop lights but if we turn the climate control dial to off on the dash ( meaning no heat or no AC ) the idle is normal. Return the climate control dial to any heat setting: defrost, vent, floor etc and the engine idles up and down, sometimes almost stalling. The AC works fine. At highway speeds all seems normal. Is this a case of the WAS relay in the CCRM engaging the compressor at the wrong time ? It sounds like the compressor is coming on when the idle drops.