I had the same problem last week. Everything was doing fine and I was feeling really good about FMQ, UNTIL I looked at the back when I had to replace the bobbin. Very very loose stitches. (Problem only started for me on the last bobbin change) Took me an hour to remove it all and I just could not get the darned machine (Juki TL98E) to sew a good stitch. So, cleaned out everything, brought out the canned air, couple shots, removed that little thingy in the bobbin, cleaned that all out, new needle and now she is purring like a kitten again!!!