00 civic lx surging idle

just purchased a 00 civic lx dirt cheap,needs some body work is main reason.engine ran fine except for a periodic idle surge,so i removed throttle body,iac valve etc.it was really dirty with a lot of carbon build-up.also replaced pcv valve,when i put it back together the idle surging is worse than before.it idles fine at first when cold but as soon as rpms kick back it constantley surges between 1000-2000 rpm.i am pretty sure its a vacuum leak.when i cover throttle opening the idle come down and smoothes out.shouldnt it cut off when i do this if there was no vacuum leak?i even reset ecm to be sure of that.any suggestions i am new to working on hondas

try screwing in the set screw on the throttle body..does it have a fast idle control valve??