I took the z axis off tonight to check it out, there were a couple loose nuts there. I tightened it all back up and it seems to be working like a champ now. I think the threads are slightly stripped on one of the couplers, I may at one point do a through bolt drill through both the coupler and acme screw just so that I know it'll never slip on me.

Regarding maintenance, what all maintenance needs to be done other than cleaning off and oiling the cold rolled steel and the acme threads?

It is a fineline automation machine,