could be a vacuum leak, or you may need to adjust the IACV duty cycle.
there are several ways to find vaccum leaks. some use soapy water in a spray bottle or carby cleaner, some use a smoke machine. search on google and youtube
in terms of adjusting the duty cycle, you will need a Hondata S300 in your ECU (or another kind of USB tuneable unit). you hook up a laptop, and download the map. then go to the "idle" tab. play around with the duty cycle while the car is idling (at running temp) and click file>upload every time a change is made.
the other possibility is maybe the vacuum lines to the TB/manifold are going to the wrong places? or maybe one isn't hooked up?