Try using different types of thread on a practice sandwich. I ended up buying Isacord...online. and that helped a bunch. It is a poly thread I believe...some machines prefer one brand or type of thread...go figure. Mine prefers cotton thread or the Isacord. I ended up buying a machine that only does straight stitching and that ended my bobbin problems. My stitching improved a thousand per cent after months of practicing FMQ. Juki solved my probs.