Check the throttle body for cracks.
Check for restriction in the vacuum port or passage.
Check for interference when moving the accelerator cable.
Throttle valve set screw was adjusted in the production line with the air volume (0.516 ± 5% g/sec) during idling. So please DO NOT ADJUST IT voluntarily.
When the idle rpm is out of specification, check the relevant sensors and their input or output value first.
The throttle body does not need to be cleaned because carbon in throttle body does not aftect the system's operation at all.