1999 honda civic

I have a 1999 honda civic ex 5sp 188k. Today CEL came on scanned p0505 idle air control. Rpm is jumping around from 1200-1600 or so little throttle and the jumping increases in speed until above 2000 rpm. As i was checking the iacv playing with plug the idle dropped to normal. Then it went back up unplugged it and my idle dropped down to just over 600rpm where it normally idled. When unplugged of course i got a new code p1508 iacv circuit malfunction. Plugged back in and idle jumped again. Does this indicate the valve is bad. The idle on the car has been increasing the last few days before the code popped up. Any help would be appreciated thanks.