i own a 1996 nissan pathfinder in texas ever since i purchased this vehicle the air conditioing works best when the car is moving. the coolant is full and the compressor seems to work fine. but when in idle the air just get warmer and warmer. any suggestions

If you have had to add freon in the past non condensables (air) may have gotten into the system. May have to find and fix the leak and put a vacuum on it. Be sure the condenser is clean and you have enough freon in the system.