Sounds like a job for our new Digital Current Probe (DCP) option for the MP3000E series
It measures the actual cut current (non-contact probe on the workclamp wire) and dispalys it on the MACH screen. Product is in beta testing now but only works with our DTHC products.
Short of KNOWING the actual cut current you can't troubleshoot it on the electronics end. A regular AC current probe won't work.
Turn your air pressure up a bit and make sure the air is CLEAN and DRY. Use the right sized nozzle. adjust your pierce height.
Have long, meaningful conversations with the vendors that sold you the equipment.
Best of luck:
TOM Caudle
www.CandCNC.com