I have similar problems with Saitek Pro Flight X-56 Rhino.
It started out with weird minor slow turns inflight without any control inputs on my part. It was manageable. I rationalized it was wind gusts or something. Annoying , but manageable.
Within a week, a new problem cropped up. When I taxi, the airplane veers sharply left or right so strong I cannot override it with full nose wheel steering! I guess that maybe it is an AI control problem. I check settings and AI is set to off except radios. So I start slewing myself back to where I need to go on the ground. Annoying, but manageable.
Within a week, the throttles begin to make fairly rapid large (greater than 25%) increases and decreases with no throttle inputs whatsoever. It starts out occurring not all the time, but some of the time then all the time.
No aircraft is flyable now. So I figure it is time to recalibrate the throttles. I now have no throttle control at all. No response whatsoever.
Help somebody! The X-56 is less than 1 year old and was expensive! Anybody have any ideas to help me out of this conundrum?