Manifold Absolute Pressure (MAP Sensor) Characteristic

• Manifold Absolute Pressure normal readings at Idle (750 RPM) = 4.6 ~ 5.2 psi and around 890 ~ 900 RPM should reads around 5.5 ~ 6.4 psi.
• Low MAP sensor readings indicates low loads therefore the ECU / ECM will command injectors to deliver less fuel  vice versa higher MAP sensor readings means more loads thus more fuels injected for combustions,
• High MAP sensor readings at idle could be caused by 
• vacuum leaks
• bad throttle body butterfly mechanism
• throttle cable adjusted to much cause the throttle butterfly to open slightly allowing more air to enter the intake manifold
• The result of higher readings of manifold pressure will cause poor fuel economy.