AFM (Active Fuel Management) lifter failure in your 2016 Chevrolet Silverado at 100,000 miles is an unfortunately common problem with GM's cylinder deactivation system. When these specialized lifters fail, they cause misfires and potential engine damage.
What is AFM?
Active Fuel Management deactivates four cylinders under light load to save fuel. Special lifters on these cylinders collapse on command to disable valve actuation. When these lifters fail to collapse or expand properly, misfires occur. The complexity of this system is its weakness.
How AFM Lifters Fail
The AFM lifters contain an internal locking mechanism that wears over time. Failed lifters may stay collapsed, causing a dead miss. Others may not collapse, keeping all cylinders firing and triggering AFM codes. Debris from failed lifters can damage camshaft lobes. Once one fails, others often follow.
Code P0300 Connection
Random multiple misfire codes often indicate AFM lifter problems when cylinders 1, 4, 6, or 7 (the AFM cylinders on this engine) are involved. Single-cylinder misfire codes on AFM cylinders strongly suggest lifter failure.
Repair Options
Complete AFM lifter replacement is the thorough repair - all eight AFM lifters should be replaced. Many owners opt to install an AFM delete kit that replaces AFM lifters with standard lifters and reprograms the ECM to disable the system. This prevents future AFM failures. Expect $2,500-4,000 for comprehensive repair.