There is one inescapable issue all vehicle owners deal with – fuel quality. Gasoline engines get dirty on the inside, ...

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 ...

As you've heard many times, your car's engine is nothing but a big air ... forced to draw air through a partially closed butterfly valve that creates a vacuum in the intake manifold.