My daughter drives a 96 C220 with 85K. It has had an intermittent problem 3-4 times now. After driving, then shutting off, will not restart. Engine turns over, but is either not getting gas or spark (I don't know which because I am never there to test). No commonality in weather or length of trip. In all cases, problem seems to go away just as mysteriously as it appears. The last time it happened was 2am Sat morning on a road trip from FL to IN. At a gas station in TN where they stopped for a drink (no gas needed), it would not restart. I told her to add gas anyway just in case. She opened the cap and added a gallon, and the problem went away. She drove it to the pump where it only held 4 gallons, so it was not low on gas. Could it be something related to opening the cap on the tank?She does not recallloosening the cap on any of the previous occasions. I am looking for any starting points since, like most fun problems, will not repeat itself when I am there to diagnose! Thanks for any help....