I have a 97 Accord 4 cylinder automatic. After I have been driving with the AC on for a little while, I can hear (and feel) the compressor clicking on and off. Once it starts it will continue to click on and off every 2-3 seconds until I turn the AC off. It starts to occur very quickly when I am driving in the city, but it takes a little longer to start happening when I am driving on the highway. I checked the pressure and it was a little high, but not too high, so I let some of the refrigerant out to get it into the correct range and it is still occuring.

Also, the refrigerant I let out had a greenish tint to it. Is it supposed to?

Anyone know what might be causing this? Any help would be appreciated.