The next step is to have someone do a cylinder leak-down test which uses a device that pressurizes each cylinder with air pressure and measures the percentage of pressure loss. Most shops that do engine work should have the tool. One can then determine the health of valves and piston rings. If your problem is not related to clogged or leaking hoses, you probably have worn piston rings which causes "blowby" and the cure is expensive, honing or re-boring, piston rings or new pistons (if boring is required).