A sobriety ignition interlock system including an engine control device and a method for managing available vehicle engine power using the sobriety ignition interlock system. The engine control device includes an engine control processor (ECP) that is electronically connected in between an engine control unit (ECU), an engine sensor assembly, and a sobriety processor. The sobriety processor determines a sobriety level of a vehicle driver and sends a corresponding sobriety signal to the ECP. The ECP intercepts an engine signal transmitted from the engine sensor assembly to the ECU and manipulates the engine signal according to the sobriety signal, in order to manage the available power of the vehicle engine.