The 1998 Chevrolet Blazer came standard with a 190-horsepower, 4.3-liter Vortec V-6 engine. As with all engines of its era, the 4.3-liter Vortec engine uses numerous sensors strewn throughout the drivetrain. The manifold absolute pressure sensor monitors pressure changes in the intake manifold and relays this information to the Blazer’s computer system so it can adjust the air-to-fuel ratio accordingly. Replacing the MAP sensor is straightforward, but finding it can be a little difficult if you don’t know where to look.
Open the Blazer’s hood and trace the air filter outlet tube until you reach where it connects to the top of the engine. Look to the passenger’s side of the end of the air filter outlet tube and find the square electrical component connected to the intake manifold, this is the MAP sensor.
Unplug the MAP sensor’s wiring harness, by lifting upward on the locking tab and pulling the harness from the MAP sensor.
Pull straight upward on the MAP sensor to remove it from the intake manifold. Pry upward on the MAP sensor’s rubber grommet with a flat-head screwdriver to free it from the intake manifold. Remove the MAP sensor and its grommet from the engine compartment.
Press a new rubber grommet, which comes with the new MAP sensor, into its hole in the intake manifold until its flange seats on the intake manifold.
Line the MAP sensor up with the two locking tabs on the intake manifold and press the MAP sensor into its grommet until it sits flush on the grommet.
Plug the wiring harness into the MAP sensor.
