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What Are AFM LIfter Failure Symptoms?

AFM is one of the essential systems, after all, it determines the fuel management in the vehicle. The fault or issues initiated in the system will result in the cessation of many functions thus, causing a variety of issues.Here, in this article, we will discuss the AFM lifter failure symptoms, its working, fixations, and certain frequently asked questions related to the topic. So, let’s begin with the discussion over the content.

What Is AFM Lifter In Cars?

\AFM stands for active fuel management which is responsible for improving the gas mileage by shutting down half of the cylinders under light-load conditions to reduce fuel consumption by vehicles. It is also referred to as displacement on demand (DOD) or cylinder deactivation.


AFM is pretty good for gas mileage and can be five to seven percent more fuel-efficient under certain specialized conditions.

What Causes AFM Lifter To Collapse?

There are a variety of reasons which creates or responsible for failure of AFM lifter in vehicles. The most common causes for such faults include control issues, or oil pressure issues. However, the activation and deactivation often control and managed by the valve lifter oil manifold or VLOM.

The main function of it is to direct the flow of pressurized engine oil to the active fuel management (AFM) intake and exhaust valve lifters.

What Are AFM Lifter Failure Symptoms?

Active fuel management performs multiple roles for maintaining the proper functioning of the system in the vehicle. However, there are certain symptoms or signs which determine and help us to know the quality of AFM lifters. Thus, it would help us to know whether the lifter is bad or not.

So, let’s discuss some of the signs for determining such issues in the car. Also, these symptoms will help you for finding a solution to your problem but it is better to prevent all these signs by regular servicing of your car.

1. Sticky Lifters

It is the first sign observed in vehicles. Here, the sticky lifters remain in the collapsed or bad state instead of performing their function i.e., going up and down. As a result, whenever the lifter fails to move, the system becomes preferentially unstable to maintain the oil pressure.

It would also cause the production of annoying noises due to the internal parts of the lifter hammering against each other.

2. More RPM Causes More Noise

The presence of the faulty components in the system leads to accelerating at a higher RPM (rotation per minute). It would increase the volume and frequency of the lifter noise.

The increased volume determines the faulty AFM lifter in the car. These noises are extremely annoying and would irritate you a lot with time if not treated soon.

3. Misfires

The failing lifter creates a lot of problems in the engine, one of them is the occurrence of misfires. A faulty AFM lifter may disrupt a cylinder’s tendency and ability to mix and burn air with the fuel. The failure in this function causes misfiring of the cylinder along with slow acceleration.

Hence, whenever you experience such misfires from your car, it is better to park it in the side and call the mechanic.

4. Dead Cylinder

It’s another symptom observed in the vehicles. Here, the malfunctioning or bad lifter will cause the pushrod to bend and fall out of space. When such a situation arises, it may lead to a dead cylinder that might break valves, rocker arms, or even damage the entire engine.

These conditions will create severe issues if won’t treat in time. Therefore, the proper concern is needed in all such cases.

5. Check Engine Light

Is also observed in some vehicles facing issues with the AFM lifter. As active fuel management generally deals with the fuel consumption in the engine, hence the emergence of check engine lights is pretty common. As a result, when the problem intensifies, your check light will come on.

Here, in such cases, you need to visit the mechanic nearby or can diagnose the issue by yourself by checking the listed error codes. The codes would either be provided with the vehicle or you can even search online. Although, the professionals know it all.

How Long Can You Drive With Bad Lifters?

Whenever you faced or experience issues related to the failing AFM lifters, we recommend you to consult the professionals for fixations as soon as possible. However, if your lifters are collapsed then you must not drive more than a hundred miles instead use those hundred miles to drive your vehicle to the repair shop. These problems are pretty severe, hence, need to correct before the situation reaches to worst.

Can Bad Lifter Cause Rough Idling In The Vehicle?

If your AFM lifters are not able to receive or pumped up as per the requirement then they signify one or the other issue related to the oil system. It generally determines or indicates that they are not receiving enough oil pressure or have gone bad, then the valves will not be opened completely. All these cases would result or causes a rough idle.

How Much Does It Cost To Fix A Faulty Lifter?

The cost of fixing the lifter may range between $310 to $520. The labor costs are estimates within $80 to $110, and the price of each part lies somewhat between $150 to $200. All these prices exclude taxes and fees.

However, these prices vary from place to place and also depend on the make and model of the vehicle. One could prevent all such expenses by regular visiting to the service center.


We hope the information mentioned above help and guides you in dealing with such uneven issues or problems. However, by the end of the topic, we also expect that you know in detail about the AFM lifter failure symptoms or signs which would significantly play an important role in tackling the situation.

If your doubts or queries regarding the content persist, please comment below in the comment section. And we will surely exert an effort to answer all your questions as quickly as possible.