Air flow meter I think, dont actually know why air flow meter is called maf, can someone educate me?
AFM and MAF aren't exactly the same thing AFAIK.
AFM Air flow Meter - measures the rate of flow of air.
MAF Mass air Flow - Measures the mass of the air, which can change depending on altitude/temperatue etc.
Taken from WIKIPEDIA :-
An air flow meter, commonly abbreviated to AFM, also known as an air consumption meter,
is a device that measures how much air is flowing through a tube.
It does not measure the volume of the air passing through the tube,
it measures the actual speed of the air flowing through the device in a defined time segment
A mass air flow sensor is used to find out the mass of air entering a fuel-injected internal combustion engine.
The air mass information is necessary for the engine control unit (ECU) to balance and deliver the correct fuel mass to the engine.
Air changes its density as it expands and contracts with temperature and pressure.
In automotive applications, air density varies with the ambient temperature,
altitude and use of a turbocharger and this is an ideal application for a mass sensor