Fester, I see you posted on ch-hanger, which was going to be my suggestion.
Similiar issues have been reportedly fixed with a power supply replacement in the past. (Supposedly, the computer power supply is defective or at or near max draw, which causes power fluctuations to the USB ports which in turn power the CH devices. This flakey power causes the pot readings to fluctuate as well, as they are essentially voltage dividers - and if you divide a fluctuating value you get a fluctuating result.)
Frankly though, I'd give worlds to have my Logitech Wingman Force back. It was truly the most realistic stick I've ever owned, although even then Logitech had begun to implement the 1/2 gymal design that made their newer sticks utter garbage.
As much as I loved my MSFF stick with the Simped pedal mod (not the one Simpeds sold, but my own) , having the hat switches go every six months just got to be too much to deal with.
I swear to *** someday I'm going to sit down with the power saw, drill press and and lathe and build one that's meant to last a life time. In the meantime, the CH stuff seems to be the best of what's available. Not that mine have been trouble free, either.
EDIT -> PS. Mine (once I performed the fixups I described on CH-Hanger) are perfectly stable in both the Control manager, and in AH. In Control Manager, full deflection is 0 and 255 on all axis, and center is exactly 127.
In AH, full deflection is 0 or 255 at one end and 65535 at the other on all Axys, and center is 32767.
I do use Control Manager and map all 3 devices into 1 control, so that I can still use it as a single device for those games that support only one, not that I play them any more (WB 2.77, Mechwarrier).