Here's the problem. My A/C works fine while i'm on the highway at WOT but when I come to a stop it just stops blowing cold & the car shakes like crazy almost like it wants to shut off. I did notice that the clutch on the compressor spins then stops. Could it be the A/C Clutch Switch or possibly the A/C Compressor Clutch or could it just need some 134a? Any suggestions sure would be appreciated. Thanks in advance.