my integra idles the same way it drops between 500 and like 100 rpms nearly cutting off,but it was a vacuum leak,then my vtec quit working and it was a pig,when vtec stopped working it was throwin the check engine light,only when i ran it the check light would come on so i turned the car off for 30 secs to reset the ecu then when i would get on it again it would throw the check light again,thats what happened to my car not sayin its whats wrong with urs but i had those similar probs and thats what i did so id check your vtec wires and oil cuz my car was slow as piss without vtec sorry if this doesnt help just thought id let ya know i had the same probs, hope ya figure it out.