Engine help

[azle]

1999 E320 wagon, running fine, yesterday while my wife is pulling in the driveway the car stumbles she thinks nothing of it. Later that evening she goes to a ladies party in our neighborhood and the car stumbles and dies for good. I think maybe out of gas, put in two gallons no go. Pull it home and put the key in the run position and there is a sound coming from the back of the intake manifold sounds like a gyro that is not all together spinning right it has a change in sound and pitch. The car will only make an attempt to start nothing else. There is only one other odd thing going on, the MPG has dropped about fifty/sixty miles to the tank.
Another question, can you scan if the car is not running? Also the CE blinked as the car was dying on my wife and went solid as the car died completely. Any and all recommendations and ideas will be greatly appreciated, thank you.