weird idle after CAI install

Today a friend and I installed new speakers, a new head unit (huge PITA) and a cold air intake. I have the battery disconnected for some hours and after getting everything connected I reattached it and drove the car, the car starts fine and drives fine but my idle is kind of weird. when I shift into neutral to coast or stop for a light/ stop sign my car would sometimes drop below 500rpm. When I am waiting a light it will bounce around then stay around 700-800. I know sometimes when the battery is disconnected it resets the ecu and the ecu needs to "relearn". I am just wondering if that is the case or if the CAI may have some change in it?

You might have forgotten to reset the ECU. To do this:
Disconnect the battery, pump the brakes once or twice to drain any charge out of the system, wait 10 min or so, then re connect the battery and start the car. Now let it idle for another 10 min. The ECU will learn your new air-fuel ratio and the car will run like it should.