I'm a total noob so take this in the spirit it is given. I was having similar troubles with FMQ. I figured out that in my case it was the brand of needle. I can get away with inexpensive ones for piecing and general sewing but when I FMQ, I need a different quality of needle. I have Mom's machine with all her accessories and I can't tell you for sure what brands work because the packages don't have labels anymore. But I know what doesn't work for me - el cheapo needles. I now keep my FMQ needles in a special box, labeled so I can find them. I use size 14 btw. Even with this knowledge, I am FMQ right now and one of the fabrics in my quilt causes my needle to skip stitches now and then. Just one particular fabric. Ugh. I've changed needles over and over and that fabric keeps giving me a hard time. I'm compensating by stitching very closely on that fabric so if a stitch is missed, others will fill in. Not sure if that's correct, but that's my plan.