Cold start low idle problem

When i start my car in the morning or any time from when the engine has had the oppurtunity to cool down, it will start ok, but it doesnt do its whole high idle thing to let the engine warm up. it just kinda starts idling and at like 500 rpm. I am asuming one of my sensors is faulty sence it only does this accasionally. Any idea's of what it could be???

cold start injector switch? btw, what year, engine, tranny.... do you have, i'd be able to pinpoint the problem more accurately. Thanks

Jay

94 22re 5speed