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Q: I have a 2008 Chevrolet Impala SS with a 5.3L engine. Is there an inexpensive way to get rid of the problematic Active Fuel Management (AFM) system that’s constantly causing cylinder # 6 to have collapsed lifters?

– Steve from Spartanburg, North Carolina

A: In 2007, General Motors (GM) introduced its so-called active fuel management (AFM) cylinder deactivation system in its small-block V8 engines. The technology uses special engine lifters to deactivate four of the eight cylinders under light-load driving conditions to improve fuel economy. 

AFM lifter failure is a well-known problem that affects countless GM vehicles. Many drivers, like yourself, look to disable the system after experiencing repeat failures. 

There are a couple of ways to disable or delete the AFM system. First, there’s an AFM delete kit, which is the choice that’s usually recommended when one or more lifters have already failed. The setup replaces all of the AFM components with standard, non-AFM parts.  After installing the delete kit, there are several additional steps that must be taken for the engine to run right, including replacing the camshaft, reprogramming the engine control module (ECM), etc. 

The second option is to use an AFM disabler that plugs into the car’s onboard diagnostic port. As you might guess, the disabler instructs the ECM to disable the AFM system. Usually, this option is only recommended when the vehicle has not experienced prior failures with the AFM system. You’ll find that the disabler costs less than the delete kit.  

Even though these workarounds sound good in theory, it’s important to note that there are issues associated with disabling or deleting the AFM system on a street-driven vehicle. 

First and foremost, because the AFM system is designed to reduce vehicle emissions, disabling the system is considered tampering with emissions equipment, which is illegal per section 203(a)(3) of the Clean Air Act. There may also be state and local laws prohibiting the use of an AFM delete kit or disabler.

Also, when you modify a vehicle, you run the risk of creating new problems that weren’t there before. For instance, if you reuse the stock oil pump after deleting or disabling the AFM system, you run the risk of oil being sprayed from the pressure relief valve onto the bottom of the cylinder walls, causing the engine to burn oil. 

When one or more of the AFM lifters fail, many repair shops choose to replace all of the lifters, along with the lifter buckets, camshaft, and Valve Lifter Oil Manifold (VLOM) instead of deleting or disabling the AFM system. Usually, this is the best option if you plan on keeping the car for a long time and driving it on the street.  

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Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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