How do I stop squiggly lines when it outlines?

my belts are tight from what I can tell but when it outlines on the y it seems to shake the machine which looks like its causing my lines to shake. Any idea how to fix? Ive slowed it down made my min power 5% less than my max. Any help would be great

Make sure machine is on solid surface and not wobbly. Looks like feet may be adjustable.