Hi ang Civic ko medyo tumotopak ang idling kasi pag naka stop minsan ako umaakyat baba ng mabilis para kang nag rerev na tuloy tuloy na up and down from 800 umaakyat sa 2 tapos bababa mabilis siya tried cleaning airfliter and ung sensor sa tubo
sir you're problem might be the ICV or idle control valve. this is located at the rear of the intake manifold. it controls the idle of the engine specially when a/c is on.
cleaning usually does the trick. except if the ICV is damage. then you can replace with surplus or new part.
i encounterd also that problem nung nangyari sa akin yan nilinis din tapos nilagyan ng silicone yung throttle,,edi ok na tapos pag tagal blowby mine is a b16v laki ng nagastos ko