The evaporator is on the rear drivers side. It is clean and I haven't put any gauges on it when it shuts down. It only happens after I have been traveling for a couple of hours. At idle the fans are blowing behind the evaporator so I guess I should stop and check to see if they are blowing when it quits cooling. I will also check to see but my guess is the compressor isn't running when it quits cooling.
It does cool very well at first. Just doesn't make any sense that it would cool so well and then stop, let it idle 5 minutes and it goes back to cooling.