Originally Posted by mkc

If this is a fixed ruler foot and not the ruler "toe" that goes on the convertible foot, it's likely that the foot is too high off the fabric sandwich and it's allowing the thread to deflect the needle too much when you move the fabric.

If it's the toe on the convertible foot, you can adjust the height of the convertible foot so there is less needle deflection.

Big skipped stitches, if there is no hole from the needle, can mean you are moving the fabric too fast.