Would start with inspecting the entire air intake assembly, from the airbox -> back to the throttle body, looking for missing hoses, cracks, etc..
and cleaning the IAC valve & Throttle Body intake and plates using Carb Cleaner, and if the MAF hasn't been cleaned recently, cleaning the MAF with (CRC-Brand) MAF cleaner,
and installing a new air filter if older than (6) months / cleaning out any debris from the airbox using a shop vac and/or compressed air..
a general inspection of all vacuum lines / ports from the Intake manifold to respective components might be a good idea also,
In short, I'd start by checking for illegal air, and cleaning/making sure the throttle body/IAC Valve, and airflow is operating as expected,
Lots of posts on how to clean the IAC, Throttle Body, and MAF sensor, but if you have questions, post back, we'll try to help,
Regards,
GottaCruise