How to Fix AFM-Induced Lifter Failures in 4.3 L Silverado

Active Fuel Management (AFM) helped GM trucks improve fuel economy by deactivating cylinders under light load—but on the 2014–2018 Silverado Sierra 1500 4.3L Gas Engine platform, AFM-related lifter failures have become a known headache for some owners. A collapsed AFM lifter can trigger misfires, ticking, poor performance, and even top-end damage if ignored. This guide breaks down what’s happening, how to diagnose it, and the best repair paths—from lifter replacement to full engine swaps through BS Auto Supplies.
AFM disables cylinders and conserves fuel by selectively collapsing valve lifters. Over time, those special AFM lifters can stick, collapse, or fail to re-engage properly—especially when oil quality slips, debris clogs the lifter oil passages, or high mileage wear sets in. The result: persistent valvetrain noise, uneven cylinder performance, and misfire codes. AFM lifter failures are frustrating—but fixable. Act early, diagnose correctly, and choose the right repair level for your truck’s mileage, workload, and budget. From lifter kits to fully reman engines, BS Auto Supplies helps you bring your GM V6 back to strong, reliable service.