Make sure you add Fuel Additive to the engine and fuel system in your 2006-2007 Chevy/GMC 6.6L LLY/LBZ Duramax at every fill-up. Most additives are specially formulated to reduce smoke, improve engine performance, as well as clean fuel and engine components. Many fuel additives enhance lubricity and cetane while others are specifically designed for cold weather and to reduce diesel fuel from gelling in cold weather. Shop today and find the additives you need for your vehicle from XDP, Lucas Oil, FPPF, Hot Shot's Secret, Stanadyne, and more!