06 4runner 4.0 Automatic. When the Air conditioning is on or defrost is on and it cycles on and off, my RPM's fluctuate from 500 to 750. It is annoying at a traffic light where you have to have different foot pressure on the brake pedal. At a traffic light this may happen 3 or 4 times so it is cycling quite often. I know that when the air compressor kicks on the rps's have to keep up but something seems like it's not right! Your thoughts please?