Two oilfield diesel rigs were having their tanks cleaned in Houston last week (Monday a week ago) when the trucks exploded. 2 workers were killed and other workers nearby heard the idling diesel engines on both trucks start to race just before the explosions. The preliminary thought is the tanks contained a combustible fluid that enriched the surrounding air, while the tanks were being cleaned, and this contributed to diesel engines accelerating. I'm not familiar with the injection rack controls on these trucks but they did not seem to have speed limiting automatic air shutoffs enabled. I've never seen an MB sedan with automatic air shutoffs. I would not recommend introducing methane into the intake air unless your looking to verify a hypothesis. Two similar accidents had been previously reported according to the news article.