Hey, thanks for the tips. I'll try thes out and keep you posted. I've changed blades and grips. Only because I had too. Right now they track good. But I'll check everything out like you said. The reason I though of the battery, because of the time frame. I changed batteries and sometime after I notice the erratic change. It's like the blades will go to a negative pitch and then back to normal.
Thanks again, Lenny