I have a Janome Horizon 7700 and I get skipped stitches when using the ruler foot occasionally. Usually I can correct it by adjusting the height of the foot. I get skips more often when the foot is too high above the surface of the quilt. I also had a problem recently quilting with invisifil and decobob, and as soon as I changed to isacord, I had no more skipping. And also make sure to check your needle. When I took my needle out to change it, it had a curve. I had bent it by creating too much pull on the quilt while quilting. There are so many variables, that sometimes it is a challenge to get the results we want in our quilting.