I'm working on a product for limp sticks. Gonna call it Skyagra.
It's for AH pilots, tho', not their hardware.
as an aside... if this is a force feedback (?) sticvk, there are two little sensors, one on bottom of the handle and one right below the trigger... i always put a piece of duct tape over the lower one.
you could also somehow have changed the centering forces in the SW software. double check that.
you may also have been using some of AH force feedback setting (under setup) that may also have gotten changed... check them as well.
if none of the above work, you might just have gotten a so-so stick where the centering springs are loosening up thru heavy use.