Why would a printer, a reprap in this case jog fine in manual but when i go to print the Z mainly skipps. I have adjusted the stepps from 80 to 500 and in between. Adjusted the currect VREF from 300mv to 1.5v and in between and it still continues to skipp in the Z. The threaded rods have grease on them an the 8mm smooth rods are lubed. I had just printed a 1 hour print but now it decides to skipp. Everything slides very well. RAMPS 1.4, Marlin, Repeiter. Thanks
Could be acceleration or jerk speed set too high in firmware, I don’t think acceleration is applied to manual jog moves but is to programmed moves.
The Z axis jog speed in Repetier (Printer settings > behavior > Z axis travel feedrate) is likely set lower than the speed that your gcode is telling it to move.
I found a quick fix for the exact same problem was to put an M203 X### Y### Z4 E### code which sets my Z axis MAXIMUM speed to 4mm/s…
Even if it is COMMANDED to go 500mm/s, it will only ever go 4mm/s.
The firmware originally allowed up to 25 or so, which was fine manual jogging and for most programs, but it ALLOWED the machine to move faster if I mistakenly told it to move too fast.
I now have M203 X150 Y150 Z4 E40 in my start-code for every part, saves your axes and extruder from killing themselves 
I would say you guys are correct. i sliced the same file in Slic3r, Cura previously and it will run. I have implemented @Jarred_Baines and has been working fine with it.