Symptoms of a faulty mass airflow sensor include hard starts, stalling after starting, engine hesitation during acceleration and engine hiccups. Excessive idling can be another symptom.
A faulty mass air flow sensor may also have similar symptoms to low fuel pressure, which indicates a bad fuel pump. However, a mass airflow sensor problem provides a specific code if read by a diagnostic tool and this is usually the easiest way to isolate the problem.
Mass airflow sensors detect the amount of air entering the engine and pass that information to the Engine Control Unit. Information about air mass is essential to the ECU's ability to deliver the right amount of fuel respective to the air in the engine. The engine depends on the exact ratio of fuel and air to operate properly. If either the air or the fuel amounts are out of balance, the engine performance is likely to suffer.
Cleaning the mass airflow sensor on a regular basis, such as when the oil or air filter is changed, is a good preventive measure to save money on replacing a faulty one down the road. Clean the sensor by removing it and using a product specifically made to clean it. Rubbing alcohol can function as a great cleaning solution. After cleaning the sensor, be sure to let it dry before reinstalling it.