When i got mine it had set on the showroom floor for 18mo and only had 158 miles. It quickly developed a #3 misfire which turned out to be an injector. You can swap the coils and see if the miss moves and listen to the injectors and compare the click or lack of. Mine was not working but when i tapped on it, it started working, so I cleaned the injectors and it has been fine for the last 25k. A minor miss will turn the light on but if is really bad the light will start to flash and then it should definatly not be driven then.
________
D platform