i would still get it tuned. if its a washed ring, tuning will make the cylinder come back. i dont see how you can say its "not making the power its sposed to" when you dont even know what the a/f ratio is.

what if its running 9:1 rich, or 15:1 lean?

tune it, then see what happens, if you tune it an it makes the same power, then yes you got issues.

i think everyone is jumping the gun personally. but good luck no matter what you decide