Mine is doing the same thing. I posted a question also. I noticed that my compressor clutch was disengaging when stopped. It will come on for a second or 2 then drop out for about 5 or 8 seconds again. Its not staying engaged long enough to cool. Check your clutch. I dont know yet whats cousing this but if I find out I will reply back if you'l do the same. I think its gonna be a pressure switch or stat.