The cabin smelled of fuel and mechanical issues for several minutes before the flight crew made an announcement that the plane was having a mechanical issue. The smell was strong -- took up the whole cabin -- and made me nauseous; other passengers were also plugging their noses and looking around, confused. It was also scary because we didn't know if the plane was going to take off smelling the way it did. The pilot eventually announced over the intercom that the flight crew was 'checking with Atlanta' about a mechanical issue, but he didn't address the stench inside the cabin. It eventually dissipated, but an explanation or an acknowledgement of it would have been helpful.