Hi 737_800
I had the same problem, and it seems to be rather common with the Saitek throttle quadrant. You most likely need to clean the potentiometers, which over time get dirty. On YouTube I found a video that very clearly shows how to do the cleaning. When done my quadrant was as new.
The URL of the video is
https://www.youtube.com/watch?v=KHaENjHvFJQ
Success,
Dirk