I am replying to my own message sent in March in order to send out some info. Recently stopped by my local dealer and mentioned the problem I was still having with the Pfaff. Only now, after attending a seminar they have learned that there is a quirk in some of the QE4's that causes the thread to bunch up after sewing along nicely for varied periods of time. I found the only home remedy was to remove the thread, rethread the machine and remove the bobbin and put it back in. The shop was able to repair the problem finally with the addition of some kind of gizmo inside and I was told the newer models already have the gizmo attached. Just wanted to follow up... so far, it's working great!