Make sure that gunk isn't actually gelled-up ethanol. With this newer ethanol laced fuel, older engines, like your 2003, tend to get that kind of gunk in the throttle body because that fuel is pretty much crap. It's really hard on your engine.
It could mean that the gasket is either blown, or the oil that you are using is inappropriate and affected you engine. You should have it checked out by a professional mechanic/car expert for proper fixing.