Maybe you could ask nicely if they can tell if your failure is an intake valve as well? Not sure if the replacement engine will have an intake manifold on it, so he might have to pull it anyway, or may be able to see by borescope. Also if they wana show you the spark plug...take a pic for us. Alot of talk about leanout/detonation...but the spark plug wont lie about that!Great info, thank you! My fear is a tech missing something too…and then the problem just gets worse down the road.