If you find oil in your intake manifold, it's not something that should be ignored, but what has caused it isn't always clear ...

The manifold absolute pressure sensor reads the amount of pressure or vacuum (also called “engine load”) in the intake manifold, where outside air is divvied up in proper amounts and ...

The positive crankcase ventilation valve releases exhaust gas and unburned fuel from the engine block into the intake manifold. All engines allow some exhaust gases, unburned fuel and oil to ...