I went to a retreat last year and a fellow quilter is the person who told me about keeping my backing and batting larger so I could test the tension with a strip of fabric. I clean the bobbin area thoroughly and oil it every time I change a bobbin and test the tension in the bobbin case too. Then I test the stitching, using a long handle mirror and flashlight. The timing went out immediately after we got our long arm due to my putting the needle in backward, my fault. But after that was fixed, we have had nothing but problems with this machine. Finally, our wonderful repairman, (not the dealer) said he believes the timing is off in the main part. He is a pro at this so I will trust him. Thanks for all the good suggestions though, especially about fixing the timing myself. Maybe sometime I'll try it.