Step on the gas, there's a good chap! (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 the remainder of the clue.
Can you help me to learn more?
(Other definitions for rev that I've seen before include "In engine-room speed up" , "Clergyman, or woman (abbr)" , "Minister" , "serviceman?" , "Clergy title" .)