this is what one owner experienced
Used on a 2009 Suburban, that is substantially used for highway travel. Having the AFM disabled has not decreased fuel mileage whatsoever. This suburban was using oil due to the AFM (approximately 1/2 to 1 quart in 3,000 miles) and this is the only device made that can disable AFM without a tuner. After using it non-stop for approximately 4,500 miles - THE OIL USAGE HAS STOPPED - PERIOD! I just checked this morning and the oil has NOT budged. (2009 Suburban 36,500 Miles).