Manifold Pressure/Vacuum Sensor: Description and Operation

Engine applications using the Multiport Fuel Injection (MFI) system, which is classified as a multi-point, pulse time, speed density, fuel injection system include:
- 5.8L Federal Emissions Equipped Over 8500 lbs. Gross Vehicle Weight (GVW)
- 7.5L Federal Emissions Equipped

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
The Manifold Absolute Pressure (MAP) sensor measures the pressure in the intake manifold and provides this information as a variable frequency signal to the Powertrain Control Module (PCM). With the ignition switch in the key ON/engine OFF position, the manifold absolute pressure sensor will indicate the barometric pressure in the intake manifold.