Engine Problems Caused by Faulty Mass Air Sensor?
Many modern vehicles use fuel injection systems and a key component of this system is the mass air sensor.
The mass air sensor measures the amount of air getting into the engine and passes this reading onto the engine's computer. The computer calculates the ideal fuel flow necessary for the best balance of engine power and low emissions.
Impurities in the air can contaminate the mass air sensor resulting in false readings. This leads to improper fuel flow, excess emissions, engine hesitation, fast idling, and a host of other problems. In the long run this can damage the catalytic converter.
If the computer detects that the mass air sensor is not working, the "check engine" light will come on. Owners who work on their own cars will check the error code, replace the sensor, and go on their way.
Unfortunately, sometimes the computer doesn't realize the mass air sensor is faulty. The contaminants are enough to cause false readings but not enough to trigger the computer.
The fuel flow computer continues operating as "normal" but in reality it's not feeding the right amount of fuel to the engine. Typically the engine idles fine and accelerates smoothly, but runs rough while maintaining a steady speed. The engine may put out black smoke which is a sign of unburned fuel.
Sometimes the computer gets confused and issues the wrong error. For example the computer might indicate one of the oxygen sensors is faulty. Often replacing the sensor helps for a couple thousand miles, then the computer indicates the oxygen sensor has failed again.
The faulty mass air sensor can stump even experienced mechanics. Modern cars tell us what the problem is, and sometimes we all forget that the computer can be wrong.
If these symptoms sound like your car's problems, try replacing the mass air sensor and see if that clears things up.