Table B4307 Desired Airflow is a good place to start (as previously mentioned). Usually that means adding air. You can look at some of the Idle Tutorials on how to do that.

Another Table that can really help is Table B4343 Startup Friction Airflow Correction (depending on your OS). You can easily add 1-2 g/s to the specific ECT you are having trouble with. That extra air decays rapidly..so you just get the additional airflow at startup.

Hope that helps.