@xulfiqar @smijaz There is vacuum line that should be connected to my air cleaner box but mechanic has disconnected it and blocked it by inserting a fat screw into it. When the car is idling and I take the screw out of the that line I notice the idle rpm increase and when I block it rpm decrease again. What is the purpose of this vacuum line and what is the disadvantage if it is not connected to air cleaner box.
Edit: Car is caby cultus with approx. 100,000 km on the odo