Hello Everyone,
Thank you for all of your suggestions, its comforting to learn that I'm not the only one having problems with this Pfaff model.
I was using the Sensormatic foot when I was FMQ, thread was breaking constantly. I wonder if the spring darning foot would have been a better choice?
I lowered the top tension to 4.6(any less and it was looping on the bottom), pivot @ -2. I finally changed the needle to a 80/12 top stitch. I used various cotton threads: Gutterman,Aurifil,King Tut,Robison-Anton and Mettler; it just depended what color the thread was to match various places in the quilt panel. I put them on the machine horizontally & tried the cone thread stand.
Before I bought the Pfaff 4.2 QE, I had the Husqvarna Viking Sapphire 875, very similar machine; many of the same functions and settings & some of the same headaches with FMQ.
After my dealer returns from Brother training, the machine will go back in for repair again. Thankfully I have back up machines that know how to behave when FMQ, wish they had the throat space that the Pfaff does.
Sharon in Texas