1996 oldsmobile eighty eight LS dies going down the road

okay....here's the problem. My dad has an oldsmobile eighty eight LS while going down the road the car will die. None of the lights come on when it dies. He'll pull over and the car will start right back up. He also said that when the car is sitting idiling...that it seems the motor will speed up and then slow down. Does anyone have any ideas as to why it would be doing this.

Thank you in advance.