English to Russian Marketing Marketing / Market Research

The effects on the Chinese economy and the fact that now this middle class is under some pressure as well due to rising prices. That is sort of killing some of this appetite for luxury goods. And so, fundamentally now, luxury brands have to sort of reckon with the idea that the gas may be coming out of that engine that has really been driving a lot of their volume.

Не совсем понимаю, что имеется в виду во фразе gas may be coming out of that engine that has really been driving a lot of their volume.