I'm in the middle of that problem now. The side to side goes slow and makes BIG STITCHES. But only with my SLR on! So, I was in the middle of a graduation quilt, so I just turned off the SLR until I finish the quilt. THEN I will have to get my DH to help me lift that Voyager off the frame and take a look at the back sensors! I'm doing a panto, so I just slowed my speed control down and my stitches are actually pretty even without the SLR. Quilt height on the take-up bar can mess you up. If mine gets too high, my needle will drag on a fluffy quilt (which all my DGKs love). I check mine on every pass.