baltik

I have a professionally built ej22 frankenmotor (90 heads and ECU) in my vanagon one of the nagging issues is a persistently low idle (~500rpm) causing an annoying rough idle and vibration, at ~700 rpm the engine is perfectly smooth. I recently hooked up my AC which would occasionally make the problem worse by stalling the car. To my surprise i discovered that the builder already applied a 12v signal to the AC wire at the ECU in an attempt to raise the idle.. I have played around with the IACV as well as the air bypass screw and it runs perfect, but the ecu eventually re-learns and drops the idle back down. What other things should I try in order to solve this?