Here's the scenario...I come out of work on my lunch hour and start the truck to eat lunch with the A/C on, since it's like 95' outside. I start the truck, turn on A/C and sit and sit and sit with actually hot air coming from ALL vents. I can sit there for my entire lunch hour with no cold A/C but if I drive down the road for about 5 minutes at moving speed of 15+mph, the A/C gets cold FAST and is really cold(I had the system charged, the rear evaporator has a small leak but it holds pressure, it took almost two years to get to a point where the a/c wouldn't blow cold anymore). When I feel it get cold I turn around and go park back at work, letting the truck idle while I eat..it's plenty cold. Once it gets cold it seems to stay cold , even if I'm sitting there for 45 minutes. Although today is so hot, the truck's a/c got good and cold as i drove down the road but when I came back to the parking lot and was at idle, the A/C temp got warmer. I got out and opened the hood to see if the truck has electric fans, to see if they were working but my trucks 5.3 V8 has a clutch style fan and it was running as it always should. With the hood opened the A/C seemed to cool back down after a few minutes and then stayed cold until I had to shut off the truck and go go back to work.