Do you do many short trips? That is one of the main reasons for high fuel consumption because a cold engine runs very rich. City driving is also way less efficient than highway driving

I dont get people that buy a GC 4-Series. What do I miss out on them?

what does esysx do?

It does no damage. If the engine would have gone too hot, it would have just cut power. The only thing I am concerned about, is that she probably revved really high with a cold engine.

Is it a E87 or newer gen?