how do I disconnect the throttle govenor?Dangerous at 68 mph maximum speed. on 2001 GMC Savana 3500

This was a Penske rental cargo van and they installed a throttle govenor that will not let me go over 68 m.p.h. It cuts back and is hard on the drive line besides being very dangerous on the highway. I can't even pass a semi truck without being a problem myself to others. Its a real pain in the B_ _ _!!!Can anyone help me please?????

Asked by for the 2001 GMC Savana 3500