DFM Module GM Refresh*Some vehicles may still engage 0 cylinder mode while coasting with this product installed. During extensive testing, it was found that completely disabling this function led to undesirable driving conditions and safety concerns. Disabling 0 cylinder mode while coasting resulted in a notable decrease in fuel efficiency, with a loss of 2 3 MPG, as the engine continues to fuel and fire the injectors even during coasting. This fueling also creates an