5 Symptoms of a Bad Mass Air Flow Sensor (and Replacement Cost)

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

rough idle

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

trouble starting car

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

driving high altitude

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

engine stall

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

no power steering

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

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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.


22 thoughts on “5 Symptoms of a Bad Mass Air Flow Sensor (and Replacement Cost)”

  1. My name is Darek,
    My car delay in movement when I start to drive. The car also experienced hesitation when applying break on high speed to continue moving. Please what could be the cause. Thanks

    • That sounds like it may be two unrelated issues, but I’m not sure. I think it would be best to bring your vehicle to a shop to have it diagnosed. From there you can determine if you want to proceed with the repair yourself or have a professional replace any parts that are bad.

  2. I’ve a 2010 BMW 116 and the the check engine light has come on. I’ve checked the code and got P0101 so MAF issue. I’ve removed the MAF and cleaned it well using proper MAF cleaning spray and all was great for 3 weeks but the light has come back on. Would this generally indicate the need to replace the MAF itself? or perhaps a sign i’ve just not cleaned it well enough?

  3. I have a 1995 Buick park ave. 3800 engine- when driving down the road if i let off the accelerator any little bit, the trans. torque convertor unlocks and coasts , press down just a little it locks back up.

  4. i have a Lancer Cs and every time when i start it up-in the morning it goes off. but after i give it some gas for a while its fine. do you think it can be a problem with MAF?Plus when i start it up it indicates the engine light for few seconds. after engine is heated everything is fine.

    • It could be that the MAF simply needs to be cleaned. I’d get that check engine light code read at a local parts store, which should give you a better idea of what’s going on. For instance, if your code happens to be “P0101 – Mass Air Flow Sensor Circuit Range/Performance”, it’s pretty obvious the MAF is the root cause.

  5. So helpful. I have a 4runner 1995 3vze engine it has a hard start when it’s a petrol machine, jerking when accelerating, what can cause this could it be a fuel filter or mass air flow

    • It could be any number of things; further diagnosis is needed. I had a 98 Corolla that would stumble when you stab the gas until I replaced the spark plugs. Since this is a cheap and easy fix, I may start there if the spark plugs haven’t been replaced in a while.

  6. Thank you very much. This is exactly what is happening to my car Toyota corolla05. I have spent over 30k doing wrong thing. I got tired when they ask me to go and buy catalytic sensor. I am fed-up. I appreciate.

    • I have 2004 Mazda 6.I experience the car switching off whenever I slow down.I was told by an autoelectrician that its air flow sensor.Please is that correct?

  7. I have a Suzuki grand Vitara… It consumes a lot of fuel but doesn’t bring out smoke…I have called several mechanics but all to no success on the causes

  8. i have a 2013 nissan sentra. recently i have had a noise/like something rubbing or crackling noise, (sorry hard to describe noise). it has gotten louder. now my check engine light is on/any possible clue to what may be happening?

  9. I have a 2011 Mazda CX-7 I changed the coolant temperature sensor and the crank shaft sensor and the mass air flow sensor and the codes p0117 and p061b I can’t seem to find the problem

    • Was the engine overheating? Could also be: ECT sensor malfunction, PCM malfunction, Short to ground on ECT signal circuit, faulty or damaged connectors, damaged wiring harness, loose terminals at ECT or PCM, bad radiator cap.

    • Sometime after market sensors built in China or India, looks like the oem, but the components were cheaply built and with different resistant, will not solve the problems. Get theses sonsors from the dealer.

  10. I have a 2006 dodge caravan 2.4liters two days after I got it the check engine light came on and also shows gas cap I really don’t know what it is causing the problem but really need help so if u can help me and tell me what’s the cause would b really helpful

    • Your gas cap is not tightened all the way or needs to be replaced because it no longer seals all the way. It’s actually a common reason for a CEL. Easy fix.

      • I have a Chevy sonic 2015.
        I just got the car two months ago.

        Gets very poor gas mileage. However, no other symptoms are happening other than the gas mileage estimator became erratic after I finally did a reset to my driving this morning. It was reading 28.5 before I did the reset. After the reset, it started out at 28.5 mpg and slowly counted down to 7.1 mpg. I avg 210-220 miles per a 12.2 tank of gas.

        Drives smoothly like a new car. No stalling, no hesitation, no bad smells, no rough idle. No check engine lights or failure codes.

        I’ve paid for three diagnostic tests and each test comes up without a failure code/issue.

        I’ve taken the car to eleven mechanics.

        Nobody will touch it as there are no engine lights or codes and the car drives smoothly.

        They say it can’t be the fuel lines, the MAF, the 02 uptake sensor, the TPS as there are no codes or check engine lights.

      • If you’re for sure not noticing a fuel smell, you can probably rule out fuel delivery issues of it running rich. Things I would definitely check: tire pressure, wheel alignment, stuck brake caliper, wheel bearings. Any of these could cause you to be getting the 18 or so MPG you’re seeing. If you’re in a higher gear and take your foot off the gas, does the car slow down faster than usual? If yes, it’s some kind of resistance issue as noted with the things I would check.

    • I’ve had the engine light come on after I changed my maf sensor. My mechanic told me that it is very sensitive so the light needs to be reset 8 times before the engine finally gets used to the new sensor. My car was a 2012 Nissan Altima and it only took around 5 resets until the light never showed up again. At least not yet ????. Hope this was helpful.


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