I would recommend using a walking foot, which might help. I do know that some machines do not like sewing on bulkier items. My very first sewing machine, as well as my Kenmore really preferred sewing bulkier items, cotton, not so much. Hope you can resolve the problem. I would also check your owner's manual, as sometimes machines have a way to help that problem, but can't think of it off the top of my head, but it had something to do with the pressure on the pressure foot.