The guy at Edge products described a built in safety factor in the Edge box. If the running parameters get too close to being dangerous for the engine, it defuels the engine, thus slowing it down to acceptable levels. To see backdown, go to the display section of your monitor, look for the backdown setting and set up your box to display it. My display is set for 4 parameters, EGT, boost, backdown, and engine load. I'm not so sure I buy this, but I am going to run the truck in a couple of weeks up ino the mountains, so we'll see what happens then. Worse come to worse, Edge comes out. I am almost convinced it is the Edge box that is going bad.