1998 Taurus SHO

Just bought a 1998 SHO. 89k mileage. Noticed something on a recent highway trip. When the car runs over a bump, like the seam in the highway at a bridge, the speedometer needle will drop and then go back to normal. And if you have the cruise control engaged, the engine will race like you were pressing the accellerator.

Under normal driving, cruise control off, nothing happens, but it's kinda annoying when the car feels like it's taking off while the cruise control is on.

Thanks in advance!
George