i didnt miss anything.H/c levels dont have a dang thing to do with spark plug brands.The engine is running rich at idle,plain and simple.If an injector seal was bad you would more than likely have a constant lean miss that wouldnt go away at 2500 rpm.The fuel pressure regulator diaphragm failure seems most probabable.Fuel pressure would be high at idle causing increased h/c,but when engine rpms increased the engine would be using the increased fuel pressure.Just my .02.P/s,splitfire sf6d is the money plug for my 22re.