JD 410G Loss of Power

I'm really stumped by this problem. My 2006 JD 410G has a loss of power. It comes and goes such that if I start out simply moving the machine in forward, in 2nd gear, I see a 2200 RPM engine speed, about normal, but in seconds that can drop to 810 RPM or so, even with the accelerator full on. If I come to a hill, it barely will climb it in 1st gear. Holding the accelerator full on, it can build up to 1800 RPM, then down again. Needless to say, I can't do any work with it in this condition....

JD 410G Loss of Power

JD 410G Loss of Power