Recently my engine started running very rough like a cylinder was missing. I tested the spark plugs, wires and distributor and found that they were all working properly. I even swapped them out with known good equipment just to verify it and got the same results. The air going to the engine is fine. There are no restrictions or issues with airflow. Lastly, I have verified that each of the fuel injectors are getting the correct voltage sent to them.

What I haven't done yet is checked to see what the spray pattern is for the injectors or the condition of the valves. I'm pretty sure that the injectors are working well since the issue happened all of a sudden while driving one day. This leaves the valves as the possible failure point. I know that the best way to check them is to pull the head off and inspect them, but I'm wondering if there's a way to do a lesser inspection that may shed some light on the problem without pulling the head off. Is it possible to, at least in a basic sense, determine if I have a bad valve by pulling off the cover to the cams and, possibly, removing the cams to check at least part of the valve's operation? If I were to pull off the cams I believe that the valves should all be closed, so if I was to pressurize the cylinders via the spark plug hole, then I should be able to check to see if a valve was leaking, right? Has anybody done a check like this before? Pulling the head off is pretty expensive to do if it's not part of the problem, but if it comes down to it then I'm totally comfortable doing it. I just don't want to do any more work than necessary.