The Stock CP3 fuel injection pump on your 2011-2016 GM 6.6L Duramax LML works fine for basic everyday applications, but certainly doesn't flow efficiently for heavy-duty applications you have in mind. Our upgraded Injection Pumps offer higher performance in towing, off-roading, or hauling, an upgraded injection pump can improve fuel flow and pressure, resulting in better throttle response, increased power, and more efficient fuel combustion. Upgraded injection pumps are essential for maintaining engine reliability and overall performance, especially in demanding conditions. Improve your Sierra/Silverado's fuel system performance with any of the premium replacement or upgraded CP3 pumps we offer here at Alligator Performance! Check out our full selection of Fuel Upgrades! GM Duramax Fitments: 2011, 2012, 2013, 2014, 2015, 2016 GM 6.6L Duramax.Submodel Fitments: WT, Custom, LT, LTZ, High Country, 1LT, 2LT, Pro, SLE, SLT, AT4, Denali.Some exceptions apply, please see individual product pages for specific fitments.