My machine is sewing fine,until I put on my darning foot and try to quilt. It has always workrd fine,you have seen all the stuff I have quilted with it. It isnt catching the stitches .The needle just goes in and out and nothing there. I have chaned needles twice,cleaned it well,checked the tension,,everything is like it was last night when it was working perfectly.It was even the same thread.Any ideas????