Step on the gas, my good man! (3)
I believe the answer is:
rev
'step on the gas' is the definition.
(I've seen this in another clue)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for rev that I've seen before include "In engine-room speed up" , "One turn of an engine, in short" , "Clergyman, or woman (abbr)" , "Speed up engine (colloq.)" , "Motor rotation, in short" .)