ac blowing warm at idle cools some when rpms are up freon level is good.

Sounds like low on R-134 or clutch is not engaging properly. HOW was the refrigerant level VERIFIED as correct?

Experiencing same thing and all of my research points to what sami4778 referenced. It is called the refrigerant control valve and as near as I can tell has been the culprit 80% or more of the time. I keep seeing the part as being stocked at www.techchoiceparts.com and it indeed costs $35.00.