Of course I've seen a burnt valve. I've been an ASE certified tech for almost 20 years. Actually, the old Civic I was talking about earlier had a burnt valve. I might still have it laying around somewhere. You must not work on cars very much if you don't think a burnt valve causes a misfire code. The computer does not look at the ignition coil to detect a misfire, it looks at the crankshaft and determines if there is a misfire by variations in engine RPM. Read
this article it explains what a misfire
really is.