I have a Hyundai Tucson. Recently I noticed the Aircon doesn't cool when the car is working and not moving. When I move for a few minutes Aircon starts to cool again.
What is wrong ?
If you rev the engine up and it starts to cool down, then you may be a little low on refrigerant.
If you really need to start moving, then the electric fans that are usually controlled by the a/c system may not be working. They assist in cooling the condenser at the front of the engine bay, when there isn't sufficient air flow.