I have used the above for several years and recently it started to play up on the above two axes becoming unuseable.  They are hyper sensitive and jump around when you move them making it impossible to increase or decrease revs, MP or mixture gradually.  I thought it was because the Quadrant was old and had worn out.  I purchased a new one and despite uninstalling and reinstalling the new one I have the same problem.  I recently installed and the uninstalled the CH Control Manger and I have a sneaky suspicion theat may have caused the problem.  I have cleaned the registry and tried to get rid off all references to that.  If I use the axes on my yoke to replace the x-and y on the quadrant it works OK.  The other axes work fine on the quadrant as do the switches and my CH pedals and Yoke.    I use FSUIPC and it is the same on both FSX and P3Dv4.

I rolled back my Nvidia driver from the latest one tonight and the Quadrant now seems to have decided to behave.  I do not know if the problems h=were connected but it did start after I downloaded the driver. If so computers are truly mysterious things.

 

I've been having the exact same problem. Only difference is that my V-axis is jumping around also. I'm not all that system savy, so can you walk me thru it? 

My problem seems to have been caused by installing a new Nvidia driver.  I just installed another older one and the problem went away.  I installed the older driver for another reason so it was just luck.  Hope this helps.

It helps as something to try, but I'm really illiterate when it comes to things like game drivers (where to find/how to install or uninstall).  Can you walk me through the process?

 

Sorry I just noticed this.  I am really the last one to ask.  However this may help if you use Nvidia  https://nvidia.custhelp.com/app/answers/detail/a_id/2900/~/installing-nvidia-display-drivers-under-windows-7%2C-windows-8%2C-or-windows-10