1 down: Power-walking leader rejected current races after start (7)
Looks like the answer should be wattage. Explanation, however, missing.
17 down: Enojy [sic] obscure sport (8)
I can resolve NC’s confoundings with this one: obscure = misty, sport = pe and obscure sport = mistype = enojy [sic].
12 across: Retro French artist almost curses! (4)
So who’s the French artist referred to here which makes the answer egad?