This is most likely a failed TPS (Throttle Position Sensor) or IAC (Idle Air Control) motor.
I would recommend performing a throttle body cleaning.
Next try tapping your IAC motor while your car is idling to see if it changes the idle. If so, you most likely have a bad IAC motor, if not it is most likely your TPS.
I hope this helps! Let me know if you have any more questions!