Active Fuel Management (AFM) is a trademarked General Motors technology that improves gas mileage by shutting down half of the cylinders under light-load conditions to reduce fuel consumption.Click to see full answer. Correspondingly, is AFM bad for your engine?AFM engines are 5-7% more fuel efficient. However, AFM lifters have a history of failing. Oil consumption has also been a problem. This is bad for performance.Additionally, what causes AFM lifters to collapse? We have found that most lifter faults are caused by oil pressure issues, or control issues. The AFM activation and deactivation is controlled by the Valve Lifter Oil Manifold or VLOM. Its job is to direct the flow of pressurized engine oil to the active fuel management intake and exhaust valve lifters. Considering this, what year Chevy trucks have AFM? They introduced it in 2007 with the gmt900 trucks. The 5.3 and 6.0 had afm. The 4.3, 4.8, and 6.2 did not. In 2014, all the motor choices have afm.What is the AFM on my truck?Active Fuel Management (AFM) is a trademarked General Motors technology that improves gas mileage by shutting down half of the cylinders under light-load conditions to reduce fuel consumption. It is also known as Displacement on Demand (DoD) or cylinder deactivation.