CNC Mill Y+/Y- axis different step sizes

This is my first post here so please bear with me if I am lacking any standard info or procedure in this post.

I have a 3 axis mill running linux cnc and need help diagnosing the cause for the distance difference in movement in the Y positive and negative directions. I have compensated for backlash, adjusted the scale factor, tightened the pulley, and oiled the table's lead screw but am still getting about 0.101" for every 0.1" in one direction and 0.98' for every 0.1" in the other direction. Any ideas would be greatly appreciated.

Have you tried a larger distance to see if the ratio stays the same?

if its not a mechanical issue (backlash, loose couplings etc) it might be
marginal step timing or an electrical/wiring issue where the state of the
direction pin influences the step pin.

Thanks I got it fixed by poking around the wiring in the control board, couple loose wires that were giving intermittent signals I think.