Fluctuating RPMs and code P0505

Rebuilt the d16y8 motor and replaced the IAC motor and I threw it away. I'm getting pumped code p0505 and having a idle issue where after it warms up it will fluctuate between 1,500 and 2,000 RPM's. I have 0 resistance between the PCM or whatever Honda calls it, and to the IAC. I have unplugged the IAC sensor adjusted the ignition timing to spec and adjusted the idle air valve on the throttle body so it sits at 620 RPM's at idle I plug the IAC back in and the motor going right back to fluctuating idle, performed a smoke test and no vacuum leaks found and have the Honda jumper wire they ask for to do the adjustment. I'm looking to see if I'm doing the adjustment wrong or missing a step or if or if new IAC sensor is bad right from the box.