How To Clean The MAF Sensor (GM 3.3L, 3.8L)

Cleaning the mass air flow sensor on your 3.3L, 3.8L (and some select 3.1L with a MAF sensor) is not hard at all.

In this article, I'll show you how to do it and more importantly, I'll shed some light on some important do's and don'ts when cleaning the MAF sensor on your GM vehicle.

This article covers the two major types/styles of MAF sensor. The first type was used from 1989-1996 and you can see what this MAF sensor looks like by viewing image 2 of 2 in the image viewer above. The second type is used from 1996 to 2005 and it's the one in image 1 of 2 in the image viewer.

You can find this tutorial in Spanish here: Cómo Limpiar el Sensor de Flujo de Aire (MAF) (GM 3.3L, 3.8L) (at:

If the MAF sensor, on your specific GM vehicle, is not covered by this one, the following tutorial may apply:

  1. How To Test The GM MAF Sensor 3.1L, 3.4L, 4.3L, 5.0L and 5.7L (at:

Symptoms Of A Dirty MAF Sensor

How To Clean The MAF Sensor (GM 3.3L, 3.8L)

The most common symptom, when the MAF sensor gets dirty (contaminated) is that the engine bogs down when you accelerate the car (or mini-van) but it will idle fine. But this doesn't always happen.

In some cases, a dirty MAF sensor doesn't really cause a lot of havoc with the way your engine runs.

What really sucks is that the PCM (Powertrain Control Module = Fuel Injection Computer) will not set a 'The MAF Sensor is Dirty' Trouble Code (and one doesn't exist).

But when it does get dirty you'll experience one of the following symptoms:

  1. BAD gas mileage.
  2. Check Engine Light on with:
    1. DTC P0171 (Lean Air Fuel Mixture), if your specific vehicle is OBD II equipped.
  3. Won't pass state mandated annual emission test.
  4. Lack of power when accelerating the vehicle.

The MAF sensor's job is to measure the amount of air entering the engine so that the PCM can know how much fuel to inject into each engine cylinder.

When the MAF sensor gets contaminated with dirt (and other stuff like oil), the MAF sensor still produces a signal but since the dirt interferes with the precise measurement ability of the MAF sensor, the PCM gets an incorrect measurement.

This results in the PCM ‘seeing’ less air entering the engine and thus less than the ideal amount of fuel being injected. The end result are symptoms caused by a leaner air/fuel mixture.

Before replacing the MAF sensor, it should always be checked to see if it's dirty and if it is... it should be cleaned first, since this may solve the problem.

Important Suggestions And Tips

Tip 1: The safest way to clean the MAF sensor's hot wires, is to just spray them. The MAF sensor's hot wire should never be cleaned by physically wiping them with a cotton swab. Touching the hot wires can break them (I learned this the hard way many years ago).

Tip 2: It's very important the you do not use carburetor spray cleaner or brake cleaner. Both of these are very harsh solvents and can damage the inner circuitry of the MAF sensor. If the MAF wasn't BAD to begin with... it will be -if you use these two solvents (this I can vouch for from personal experience too)

Tip 3: Do not use gasoline. Gasoline will leave a petroleum residue on the hot wires that will attract dirt, not to mention gasoline is just too dangerous to use as a cleaner.

Tip 4: Your local Auto Parts (like AutoZone or O'Reilly Auto Parts) will have the appropriate MAF sensor cleaner. The most common/popular is the CRC mass air sensor cleaner (part number: 05110).

You don't have to use a dedicated MAF sensor cleaner since the CRC MAF sensor cleaner suffers from being a tad too expensive (but it beats using something unapproved and frying the MAF sensor) and so on occasion, I have also used a regular electronic spray cleaner (also called a computer duster spray) from my local Radio Shack or Fry's Electronics store with the same success.

OK, let's turn the page and get this show on the road...