Make sure that your quilt is totally supported and not causing a drag on the needle, that causes problems too.
Use a machine quilting needle(90/14) and see if that helps and don't try to sew too fast, go slow around curves too.
I was having all sorts of tension problems with my machine and it was operator error, I'd not gotten the thread through the bobbin case right. (sigh and rip out)
Sharon W. in Texas