One problem related to engine shut off without warning has been reported for the 1998 Mercury Grand Marquis. The most recently reported issues are listed below.
While driving at 50mph on flat surface and with no warning vehicle shut off. Consumer had to pull over. *akconsumer looked through the manual and found an article explaining what to do when the vehicle is bumped and fuel shut off. The vehicle was never bumped. Consumer followed the instructions and the vehicle started back up immediately and has been running since.