"IAC in completely open state" does not mean that it is actually open. There is a certain operating range for the dutycycle used to control the valve, and if you go outside that range the valve can go into a default open mode or closed.
Try what dutycycle gets you a very high idle while hot, and use that as the maximum.
Generally the best advice can be given if you also present a config, or screenshot of your actual settings that go with the issue you're having (cranking, afterstart, injector settings and associated tables). With the report tool built into VemsTune, that should be the easy part.