Idle air controller. It's basically a electrical/mechanical valve that controls the amount of air that enters the engine when the throttle is closed.
If you look on the passenger side of the throttle body, you will see a buldge with a black part on the rear of it. It has two torx bolts holding it in.
But I wouldn't just clean/lube that. Just take off the entire throttle body and clean everything. I use kitchen soap because its good at getting the carbon off with a toothbrush. You can use carburettor cleaner if you want, just make sure its 02 sensor safe.
Also, be VERY careful when tightening the throttle body bolts back up, otherwise you will strip the threads. I just use a hand driver because you can't put as much torque on it compared to a ratchet.