An easy and cheap check would be to pull the valve cover and watch the rocker arms on #1 cylinder. If the push rods are bent you have a stuck valve. If the push rods are not bent, then back off the adjuster to see if that helps with the compression. If that does not help then you need to pull the head to see if it is a gasket (still cheap) or a piston, not so cheap. More time and work and less money. If you get lucky and the compression gets better then a set of new plugs and it should run. Keep us posted.
