engine prob

i had idling prob with my 87crx si that was partially helped with this forum. the prob was that it was idling irradically until the idle control valve was addressed (changed). now, it has a prob starting cold and when i rave the engine, after the engine warmed up, the idle drops below the normal level then back up to a stable level again ( about 1k). can someone point me in the right direction to solve this prob? thank you in advance.