Europeans have a different way of looking at luxury than we Americans do. On these shores, making something "more luxurious" usually translates to "make it bigger." However, Mercedes "baby Benz" C-Class has been proving for some time that things sold by the pound are almost always more interesting than things sold by the ton. That is, until you get a P0300 code from your 2006 C230.
Taken on its own, P0300 is one of the least helpful codes in all of auto diagnosis; it translates to "random or multiple misfire." Effectively, it means that your engine is misbehaving on more than one cylinder, as opposed to just misfiring on one cylinder as it might with a bad spark plug, dirty or malfunctioning fuel injector, or a single bad ignition coil. Usually, this code indicates that something has gone wrong with the engine's sensors, control system, or an ancillary system that affects the entire engine. Examples of the former might include a bad oxygen, crankshaft, camshaft position, manifold air pressure or mass airflow sensor. It could also indicate a bad computer, or simply an unsteady electrical connection. Hardware failures might include a malfunctioning throttle or EGR system, a clogged catalytic converter, or low system voltage. Again, absent any other codes, P0300 is generally all but useless in terms of diagnosis. Other codes that show up with it will tell the tale.
It's worth noting, though, that Mercedes of this vintage have well-known problems with the solenoids that control the position of the camshaft. Mercedes has issued technical service bulletins on this failure, and the 2006 model year is included in it. That's relevant because a cam solenoid failure may trigger a random misfire code -- possibly absent any others. It's one of the few hardware failures that will. So, the cam adjuster solenoid is definitely worth a look if you get a P0300 by itself.
