Small explosion in intake manifold

occational explosion in engine cause the intake manifold in my 1996 c280 mercedez to crack leaving a hole in the manifold. The manifold is made of plastic. what is the cause of the exoplosion.

An explosion in the intake manifold is usually caused when an uncontrolled amount of fuel is located in the intake manifold and is ignited. One thing that can allow an uncontrolled amount fuel to enter the intake manifold is leaking fuel pressure regulator.