Last year I replaced everything in front of the firewall on the AC. I still had some issues this summer and the shop replaced some O Rings and the R134A. He had put dye in and was able to find the leaks. In June center vent potentiometer was replaced and it seemed to be working ok until the latest heatwave. It works fine in the morning, but when it is really hot it has a hard time getting cool. If i play with the buttons, auto to dash, auto to dash and footwell, it will blow cooler and eventually get there. It takes anywhere from 5-20 minutes. my usual setting is 67F. when its working,the temperature is at the vents is 38-45F, there is about a 6 degree differential between the driver and passenger centervent. I'm kind of at a loss on this and it appears the Evaporator is working fine. The only thing I can think of is that some of the flaps don't close tightly and are allowing heat to mix. In any event I'm done for now. Just looking for some thoughts. I'm not up for taking the dash apart. Oh, and there are no more codes on the PDU either.

 

From the numbers you presented it sounds like your AC is working fine. Your usual setting is 67F?? Man you want it cold. I live in Texas and it really gets hot here. My normal setting is 76F. With that setting it starts to cycle after about 5 minutes on even really hot days. I think you are trying to drive it too hard. When it is over a hundred outside with the sun shinning in a setting of 67F is just way too low. Try 76F and I think you'll like it

 

HAHA, I tried that this morning, it was 71 here, nothing happened, so I put it back to 69. We complain here in the northeast if it gets in the 90's, nothing like you get in Texas. As I mentioned, the bigger issue is in the afternoon in the 90's and it takes awhile to cool down, with some vent settings being more effective than the others