The AC works great under 80° but once it gets above that the air blows hot? Anybody have an experience with this or an idea of what’s goin on?

 

Check for all engine fans to be operating properly. Or if you have a mechanically-driven engine fan, test/replace the fan clutch. Because this sounds like an issue with failure to cool the AC condenser properly. An AC mechanic can also evacuate and weigh the amount of the refrigerant in the system, and check for leaks.

AC systems DO seep a small amount of refrigerant over the years, to lubricate the compressor seal. Have you had the AC serviced in the last 5 years or so?

 

The system is full. The radiator fans seem to be working just as they should. could it possibly have a faulty pressure sensor “high or low”? Would that possibly cause it to work intermittently? Thanks!

 

When it blows hot, pull over and put in park, leave engine and AC switched on; open the hood, visually see (use a good flashlight) if the center drive plate on the AC compressor is engaged (turning at same speed as the AC belt and AC compressor clutch outer pulley). You possibly ave an intermittent slipping AC clutch (I had this on a 1998 Nissan Frontier, and fixed by removing a shim for the AC clutch to correct for wear - too large of air gap - over the years).