The engine suddenly 'roared (back) to life'. [=it made the loud sound of an engine and began running well]
The audience 'roared' with laughter. [=the audience laughed loudly for a long time]
The fans were 'roaring' [=yelling and cheering loudly] after their team scored.
(..) But the great demon was far too powerful. Snakes! Finish me, foul beast! Luckily, a blacksmith heard the beast's roars. No! Ow! Fuck! You chipped my tooth. I'm not complete. Venisti remanebis (..)2006 Tenacious D in the Pick of Destiny