Peter - how close is the mass air meter to the suction of the blower. If it's too close, say clamped right to the 90° elbow, you could be getting some backwash off the blower inlet. That will REALLY confuse the MAF meter. Also.....what did you do w/ the vent line that runs from the throttle body to the oil fill? If you didn't do it already, you need to plug the connection at the throttle body, and re-route that line to the suction of the blower (between the MAF and blower). If it's still in the stock location, you have a giant vacuum leak (which will cause a hunting idle).