I have a 2000 CLK 430 Conv which has been trouble free. Yesterday on my way to work, after starting uneventfully and driving for 10 minutes, the car stalled. It would restart then die. No malfunction displayed on the multifunction screen. MB roadside assistance thought it was the key. Cleaning the key,etc did not help. Just as I was arranging a tow, it started. I drove to the dealer, who checked it over, states it was a bad key. I'm using my spare and waiting for a new key. Has anyone heard of this before? How common is it?