The acceleration body or Throttle Body in English, is a metallic piece that is between the air inlet filter and the multiple of admission, there is where the accelerator pedal is connected, in this acceleration body it has 2 important things for the regulation:
1.- The TPS or sensor of the acceleration body (it is the one that says how much air is entering)
2.- The IAC valve or valve I slow down, this valve opens or closes as it is required to give a stable regulation.
Sometimes a lot of oil and dirt accumulates in the acceleration body, its holes and hoses causing the air not to circulate well as rpm. You have to clean the whole body, the sensor, the IAC valve and every hole you see. But if your problem is that it regulates too high, what do you have to change the TPS.