The MAP (Manifold Absolute Pressure) sensor in your Mazda 3 is a sensor that sends an electrical signal to the engine control unit to inform it of the pressure in the intake manifold. The pressure correlates to the amount of air coming into the engine, which is important for the purposes of fuel metering. Once the engine control unit has this information, it sends an electrical signal to the fuel injectors to dispense the exact amount of fuel that is necessary for proper engine operation. If your MAP sensor has failed, replace it immediately so that your engine runs smoothly and efficiently.
Open the bonnet and prop it up.
Remove the MAP sensor with a ratchet. It is located between the intake manifold and the throttle body at the front of the engine. Look for a rectangular, black object with two plastic tubes protruding from it. The MAP sensor will also have two hoses connected to the plastic tubes.
Pull the two vacuum hoses out of the sensor to remove it completely.
Attach the vacuum hoses to the new MAP sensor.
Install the MAP sensor onto the engine with a ratchet.
If the vacuum hoses do not come off easy, use needle-nose pliers to twist the hoses and then pull them off.
Wear safety glasses to protect your eyes from injury.