Question about 89 Nissan 240sx

I have a 1989 Nissan 240sx. vin# JN1H536P1KW047110. I feel it has had some type of govenor installed on it. When ever the speedometer goes to 115MPH (it's max) the engine will cut out. How is this govenor installed and how do i disable it? or what may be causing this.