Try increasing your stitch length to 3.0 or 3.5 if you have not done so. With thicker fabric a walking foot does better with a longer stitch length. The reason is because the feed dogs has to take a bigger bite ( by moving) to move heavier fabric ( layers) and using a longer stitch length helps the walking foot work better with the feed dogs. Hope this helps
Last edited by Carol Jean; 03-14-2017 at 06:47 PM.