Y axis is making X axis stall...!!

[fasteddy]

Have now re-installed Mach - no difference..
Also tried another PC, although it is a pretty low spec laptop (setup as a standard PC) - no difference..
Going to rewire my nema 23's (3Nm) in bipolar parallel today, not sure if I will be able to do the same with my Nema 34's as they are 4 wire motors, just waiting on a bit of advice on that, unless someone out there knows how to do it?

Just want to say that although I have not got to the bottom of this problem yet (and neither has Karl, my sympathies dude), I am very grateful for all the advice given.. Checking so many aspects of my machine is a real confidence booster with the level of scrutiny it has had this week, I feel like several engineers have checked my work and so far, most of what I have done seems right and a couple of things I have been able to improve..

Steve..

[Gary]

you cant connect a 4 wire motor in parallel, it is similar performance wise as if you had an 8 wire motor connected in parallel.
Out of interest does this problem happen if you disconnect the ballnuts from their mounts?
Also does the X axis stall when the Y axis is in a specific position or is it random?
My thinking is that is may be a mechanical problem with the stiffness of your machine?