Rpm up and down with vibartion in the cabin.?

Why does my car rpm go up and down when I turn my steering wheel ? also I feel a kind of vibration when turning the steering wheel left or right. Same things happen when the car is in idle and my a/c is on.. everytime the a/c will cut of and start again I feel the vibration. recently I serviced the power steering pump and changed the belt and the belt tensioner.A month back I changed the engine mounting as well. Please help me with this strange issue as its really annoying me when my car is in idle mode. Same vibration when the a/c is off and I turn my steering wheel. Its a Honda CRV 2007 model