Hey Mike,
this is a very, very frequently asked question. We have a search function here.
For the monitor intermittent issue, it is wise to add ferrite cores.
For erratic axis movement, for the Z plunge issue and for lost steps due to EMI,
- See here for more information.
By the way, we have a search function here!
that is not useful. See also the JohnMcGrath video linked in the link below. It would have been more useful to properly ground your machine (see here).
Welcome to the forum!