Anybody had this problem? I was cruising 80 mph up a hill, outside temp was 32 F w/light rain. I smelled a strange odor,car was a bit sluggish and then the panel said"exhaust over temperature." I cruised slowly having crested the long hill and the light went out. The smell gradually diminished. Dealer has had my M5 two days, finds no faults after reading the ECU and says they don't know what's up. Anybody? BTW, I always have a light oil film all over the engine compartment and have added four quarts of oil in 6500 miles. I am new to BMW so I don't have a clue. The M5 did OK at the track and on the drive back to LA from Las Vegas.
TIA,
Roland