Mine does the same. Rather than spend a 8 hour day running through those test in teh link, I sim-ply keep the temp control at 75 or so, never at "full cool". It still cools, and doesnt cut out. Also ahve to keep the rpms down ( no Italian tuneups),. I beleive the high side of the system is seeing too much pressure when its hot out and we have the controls set to full cool ( below 68 or so). That will cause the high side pressure switch to open. No A/C.