Range Technology Active Fuel Management Disable Device (Blue) Keep your vehicle in V8 mode! Disable 4 cylinder mode on all GM Active Fuel Management Vehicles. Installs in seconds! Plugs into diagnostic port with no tools needed. Does not reprogram factory ECU. Leaves no trace. Full power all the time. Increased throttle response and more consistent power delivery across the entire power band. Best for high load scenarios, such as towing, off-road, icy or snowy conditions or high speed commuting.