It is not icing up. I have turned the AC off and on when it quits working numerous times. I recently drive over 1000 miles and tried several trouble-shooting methods. During one leg of my trip, when the AC stopped working I turned the AC off for 100 miles. Turned it back on and got nothing.
But when I stop the car, turn off the engine and let it COOL for about 1.5 hours. It then works great for about an hour.
I cleaned the evaporator and checked the drain. The freon was recently charged and checked again.