If you have some noise also,I would pull the valve cover.Had one a couple weeks ago with a problem.the rocker had popped out of place.yes ohc, but it still has a rocker under the camshaft.compression will show ok,but that is because the valve isn't opening.Do a google on the problem.there are valve problems,also claims of carbon build up causing the problems(rockers popping out of place)pull the valve cover.