Sharon: I've used quilting needles and a top-stitching needle--same results, my thread shreds after sewing maybe 5-10 inches. Today I didn't put it in Free Motion mode but stitched circles (some small) and heart shapes with feed-dogs up and in regular quilt mode (C) and it sewed just fine. I was turning the quilt, pulling, straigtening it, etc. and the thread didn't do that. Now I'm really confused--you'd think it would do it all the time if something was stuck in the tension discs. Does what I wrote make sense? I just can't understand why it didn't happen when I made curvy sewing lines without FMQ mode.
Thanks again everyone--I think we're all learning more about our machines since Charleen started this thread.