I just got through watching a video on free motion quilting basics by Leah Day. She has written me a few times trying to help me with the Jazz 2 problem.
After seeing what she had over her table and sewing machine, that got me to thinking that maybe not only is the sheet of material
to make the table more slippery, but that the hole is smaller, so that the needle doesn't push the fabric down into those holes for the feed dogs and the zig zag hole.
I have some very thin Teflon sheeting. I cut s small piece just small enough not to block the two metal plate screws, or the bobbin cover, put a tiny hole in it, where the machine needle goes down into the machine, then carpet taped it over those holes.
I put the tension to nine, and dropped the feed dogs, and set the stitch length to zero. I just finished a few minutes with the machine this way, and the stitches were perfect, both straight, and curved. No lashing at all. I will work with this for a few days to make sure this is a fix of the problem. If not, then it goes to the repair shop. I sure hope this fix, this time is permanent.