One problem related to oil pump has been reported for the 1998 Buick Lesabre. The most recently reported issues are listed below.
Problem 1. . . . Pressure regulator in the oil pump locked ,causing the engine to blow. This recently happened to a friend of mine at around the same mileage. Problem 2. . . . Car has started to stall for no reason. Usually when I'm slowing down fopr a red lite or to turn. Problem 3. . . . . While drivind at around 65-70 the car has surged for an instant(sort of like when you hit the gas pedal suddenly for a second).