I own a 2007 Chevy Avalanche with the Active Fuel Management system. Every time I would slow down I would get this shudder or vibration throughout my whole vehicle. I had no clue of what could be causing this but did some research. I lubed my calipers, checked and lubed my drive shaft. I changed my spark plug wires, throttle body and was to the point of changing the wheel hubs and the torque converter. After reading some online threads I found the information about disabling the AFM by using an OBD II plug in. I figured what could it hurt. So I ordered this little device, disconnect my negative on my battery, installed the disabler, reconnected the battery and an immediate difference was noticed. V8 mode is now constant and no more vibration/shudder when slowing down. This saved a lot of money I would have spent trying to figure out this issue. Because of V8 mode your vehicle will burn more fuel but at the same time lengthen the life of your engine. I haven’t noticed a significant battery drain but it’s possible it your vehicle is not driven for long periods of time. This device doesn’t delete AFM, it just disables it.