It sounds like when you pull/push the quilt that the needle is hitting something. It is probably the side of the hole in the hole plate. Make sure you have the zig zag plate on and not the single hole plate, that helps. Make sure the whole quilt is up on your surface so there is no drag. Try to puddle the quilt where you are FMQ so you don't push/pull the needle out of alignment. If the needle is pushed/pulled enough it may be hitting the bobbin case or the edge of the FMQ foot.