My 06 MCS just shut off on my wife the other night while driving home. Two days later it failed to start at a gas station. Took it in to the dealer yesterday and luckily it threw a code and they actually traced the problem to the fuel tank sensor. Seems that the sensor went bad and thought that the car was running out of gas. If the computer thinks the car is out of gas, it shuts down the engine to keep the fuel pumps (it apprently has two fuel pumps) from burning up. This is how it was explained to me by my service advisor.

Picking the car up later. We'll see if this was actually the problem. Maybe this is what's causing all the strange shut offs with other members cars.

Oops, heading should read "No Reason" not now reason.

 

I have an 06 MCSa that used to occasionally do this while driving at very low speeds through parking lots - usually when braking around turns. Never set off the engine light, and it hasn't happened in a really long time.