The a/c is causing rpm to fluctuate when I put it in gear and keeps clicking. on 2003 Ford Ranger

When I put it in neutral or park it doesn't seem to draw down. Does someone know what is happening? Thanks for any help.

Asked by for the 2003 Ford Ranger
The A/C system is short cycling because it is low on 134A. The clicking is the clutch on the compressor turning on and off. Get a A/C service done and you should be fine.