Hi folks, C200K 2005 97k miles (new shape & has the engine with black cover on it). Engine light came on some weeks ago while in heavy slow traffic (10 mph max). Went off after hill climb and restart. Came back on in similar conditions e.g. heavy slow traffic (but not so slow this time). Went off next day. Came back on in roughly same conditions two weeks ago and has stayed on since. Over weekend took it 230 miles up motorway - fine but light still on. Coming back yesterday I came off motorway and up v. steep hill (birdlip & air balloon roundabout - infamous) climbed absolutely fine then set off from roundabout on three cylinders. Stayed like that for the rest of the way home (20 miles say. Didn't want to stop !). Stopped at destination as normal and immediately started it and all was well - light is still on but back to four cylinders. Been fine since (another 70 miles) - but still light remains on. Any clues anyone - before I suspect I spend a fortune at the garage !? many thanks ! John.