Had a weird one yesterday with the C63, driving along the A34, I was in manual mode with the paddles, as I mostly am these days. Just going up a bit of a hill after Newbury, and an EML flashed for a few seconds then stayed on, didn't notice anything at first then when I went to accelerate, the car would gently shake. Luckily was coming up to a junction anyway, so pulled over and sat at idle and it felt and sounded wrong so switched it off. Switched it back on again and it was fine, and has been ever since. Driven about 40 miles since.
I know a technician at Mercedes Reading, so went there at 7am this morning and he ran the diagnostic tool for me, no error codes were thrown which was bizarre and nothing showing out of the ordinary.
The only thing I can think of is being in 9th gear at the time, because I was talking to my daughter, I might not have noticed the revs were too low and the car and as I went to go up the hill, for whatever reason didn't drop a gear (like it usually does even in manual mode) and it kind of fell in to some kind of anti-stall or just half crapped out and couldn't get going. I did drop a few gears at the time it was doing it before turning off but it didn't make a difference, so maybe not. But just seems weird that the EML came on but no error codes were thrown.
As I say, drove 40 odd miles yesterday, absolutely fine, and the drive to Reading this morning, another 30 odd miles there and back and no issues at all. I was giving it some on the way there as well just to see if anything would come up, and nothing.
Still got me feeling a bit nervous though