Unfortunately, that is correct, The DOD AFM engines have many issues with that system causing internal damage. The common failure is for one or more lifters to fail, and the result can be anything from a tick to the loss of a cylinder from the failure. Repairs depend on what you need to repair and how you repair it. You can use the same OE parts to keep the system, or you can install a kit that removes the active management system and its related parts, you lose a bit of fuel mileage, but it means no more failures. In that method you also use a scan tool to disable the AFM in the system, so you don't set any check engine lights.
Cost-wise it depends on which option you choose. You can expect it to be between about $1,000.00 and $2,500.00 Just search for the kit you want to fit your engine based on which method you want.
Another common issue on the flex fuel versions is having the fuel composition sensor get confused and set the fuel mix wrong based upon what it thinks the alcohol percentage is.
These are the 5.3 engine codes that use AFM.
5.3 Vortec LY5, LC9, LH6, LMG, LS4
5.3L EcoTec3 engines
Much more information -
https://chevytrucks.org/delete-or-disable-active-fuel-management/
Feb 22, 2022 at 9:30 PM
