What are the worst 5. Afm years to avoid? Based on reddit owner reports, the most commonly avoided years are 2007–2010, 2014–2018, and 2019–2021 silverado 1500 models with afm or early dfm. These years show the highest concentration of lifter failure threads. What is the most common silverado engine problem? Lifter failure related to the afm/dfm system is the most common serious engine problem, particularly in 2014-2024 models with 5. L and 6. L v8 engines. The cylinder deactivation lifters fail prematurely, causing noise, misfires, and potentially severe engine damage.