I have been having problems lately with the throttle not holding center even in GPS mode. I am using the Futaba F8J controller, but feel it could be a balancing issue, either in NAZA or manually. When flying, I can stabilize the quad, but the it will drift up or down depending on the throttle position. Keeping it centered requires counteracting up or down, whereas before it would stay centered much easier. I calibrated the sticks in NAZA and all looked good. Any help would be greatly appreciated!