This has happened twice now with my 2003 CLK320. I was sitting at a light and then gave it a lot of gas as the light changed, noticed the rpm's shot way up and the engine shut down and check engine light came on. Car started right up after this happened and check engine light went out later on that day. This morning I started out kind of fast from a light then punched it and again the rpm's shot up and the car shut down. I coasted off the road and then started it right back up but the check engine light stayed on while driving the rest of the way home. Had a problem a couple of months ago also where I would give it gas and the rpm's would go up but car response was very slow compared to the amount of gas I was giving it. I cleaned the MAF sensor and that seems to have stopped for now.

 

Since the MIL illuminated, there should be a code stored. Get it scanned.