What weight thread are you using? The needle size is determined by the thread weight. I also have a 15-91 I keep set up for FMQing. It rarely skips stitches, but when it does I usually have the wrong size needle for the thread I am using. It usually likes any type of thread except the "slick" threads that were made for machine embroidery. The machine skips stitches with that type thread, also. When I use my trusted Superior King Tut or Sew Fine #50 (or#40) and the correct needle, she is a joy to FMQ with! Good luck diagnosing your problem, let us know what you discover.
Last edited by lovelyl; 05-08-2016 at 04:10 AM.