(Updated on June 22, 2020)
The mass air flow (MAF) sensor is an important component which the engine control unit depends on. When the flow of air enters the fuel injection system of the engine, the mass air flow sensor will analyze how much air is flowing in there. It will then relay this information back to the engine control unit.
From there, the engine control unit will be able to control how much fuel gets injected into the engine. As you may know, there needs to be just the right amount of air and fuel mixed together in the internal combustion chamber of an engine.
Therefore, if the mass airflow sensor goes bad then it will ultimately jeopardize the performance of the engine.
Common Bad MAF Sensor Symptoms
A bad MAF sensor is fairly easy to detect from the very beginning. You just need to be able to recognize the symptoms as they occur so that you will know to associate them with a possibly faulty mass air flow sensor.
Sometimes these symptoms may be due to other reasons, but you should still have your mass air flow sensor inspected if you experience at least a few of these symptoms that are listed below.
1) Lean Idling
When you have a lean idling problem with your engine, this is the result of too much air and not enough gasoline getting mixed together in the internal combustion chamber. The “lean” word refers to the abundance of air and not enough fuel.
Meanwhile, there is very little gasoline being burnt in the process. This will ultimately hinder the performance of the engine.
2) Difficult to Turn Over
When you put your key into the ignition and twist it, you may find the engine is difficult to turn over or start altogether. This is understandable with a bad mass air flow sensor because it will cause the internal combustion chamber to have an inadequate mixture of air and gasoline.
If the engine is going to successfully turn over, then you need to correct this problem so that the spark plugs can ignite the proper mixture.
3) Engine Drags
Whenever you increase the load of your vehicle, it will put more demand on the engine to generate enough power to sustain this weight. This means that more gasoline and air will be required in the internal combustion chamber.
But if you have a bad mass air flow sensor, then you will likely not get enough gasoline to accommodate this load. This will cause the engine to simply not have enough power output for the current demands.
4) Engine Stalls
When you start up your vehicle, and the engine turns on, you may think everything is fine. But if the engine begins to stall shortly after, then it is obviously isn’t.
This symptom may occur if your mass air flow sensor is just starting to go bad. It may send accurate airflow information to the engine control unit at first, but then it will stop doing so shortly after.
If the engine control unit cannot receive information about the airflow, then it won’t know how much fuel to inject into the internal combustion chamber.
Read also: 5 Symptoms of a Bad Air Filter
5) Acceleration Hesitation
When you step on the gas pedal to accelerate the vehicle, you may experience hesitation as you are moving forward. This is the result of the engine not receiving a steady flow of gasoline to accommodate your acceleration demands.
So, the acceleration will begin hesitating because the engine is lacking an adequate flow of fuel. This could become a driving hazard while you’re out on the road.
You should immediately get your vehicle checked by a mechanic so that you can replace your sensor and prevent any accidents from happening.
MAF Sensor Replacement Cost
The mass air flow sensor is a fairly small part but not the cheapest to replace. The good news is that it’s usually located near the top of the engine and DIY replacement is easy in most cases. Since it doesn’t take that much time for a professional mechanic to do the replacement job, the labor rates are typically low.
The replacement cost of a mass air flow sensor can be anywhere from $80 to $390 if having a mechanic do it for you. The parts cost should be between $50 and $320 while the labor costs will be anywhere from $30 to $70.
The true cost will depend on the make and model of your vehicle as well as whether the new MAF sensor is OEM or aftermarket.