Originally Posted by
leatheflea
It sounds like your quilt is dragging on something, not allowing it to move easily under the foot. Or your helping it to much. When you push it through faster than the machine is pulling you'll get a long stitch, when it drags you'll get a short stitch. Maybe a Supreme Slider would help. Is your quilting surface level or is the quilt hanging off the edges? It takes some practice to get it right. I too have problems with this but gets getting better.
Thanks so much. This has been happening to me also. I appreciate you help. I believe that you have hit the nail on the head with this answer.