Q: MAF sensor

Hi There, Yes, you are correct in that you should replace them if cleaning them did not correct the problem. Generally, these will fail when they get too dirty or have a failing voltage signal. As you may know, the mass air flow sensor monitors air intake as it is mixed with fuel prior to being injected into the motor. This sensor relays vital information to the ECM which uses this to make adjustments to fuel supply to the motor. A dirty or faulty sensor can cause an imbalanced air/fuel load to be supplied to the motor which results in an over fueling or under fueling situation depending on the conditions. This type of inconsistent fuel supply to the motor may cause a hesitation, loss of power, a jerking reaction, potentially a bit of black exhaust smoke and typically a strong smell of fuel when this sensor is malfunctioning. If you need further help with this, please reach out to us here at YourMechanic as we are always here to help.