As Elmore Leonard screen adaptations go, “Life of Crime” packs in plenty of atmosphere, but not much punch. Though faithful to “The Switch,” the 1978 Detroit-set novel on which it’s based, the film’s overall affect is flat, and its pacing ponderous. You can’t shake the feeling that the action’s in slo-mo and the attitude lackadaisical, even when the cars and characters are going full tilt.

It begins with all the ingredients necessary for a classic Motor City Leonard caper, especially a well-chosen ensemble cast skilled at juggling dark humor with drama. Suburban trophy wife Mickey (Jennifer Aniston) is married to sleazy developer Frank (Tim Robbins, with extra jowls and jocularity). He’s cheating on her with tart Miami tease Melanie (Isla Fisher), so doesn’t give a rip that a pair of ridiculously masked lowlifes have abducted Mickey, in a Keystone Kops Kidnap scene reminiscent of the one in “Fargo,” for a $1 million ransom.

Louis (John Hawkes, as understatedly compelling as ever) and Ordell (Yasiin Bey, formerly known as Mos Def, who continues to coast on that nasally distinctive voice of his) along with their accomplice, racist Nazi-memorabilia collector Richard (perennially trollish Mark Boone Junior), are unaware Frank has just filed for divorce and is thrilled at the prospect of not paying alimony should Wifey not survive. Tossed in for laughs is hapless Marshall (Will Forte at his schmuckiest), who gets unwittingly drawn into the plot while trying to score some afternoon delight with Mickey.

“The Switch”— a title that hints at a late plot twist without giving it away — had already been recently used on another Aniston movie, so that was out, but surely they could have subbed in something less blandly generic than “Life of Crime.” And word to filmmakers, enough with the creepy masks. They were genuinely terrifying in 2008’s “The Strangers,” but since then have been overused, primarily as props to distract from lack of intrigue elsewhere.

Leonard, who died a year ago, might well have given a thumbs-up to relatively untested director Daniel Schechter’s allegiance to his story. But in trying to emulate on-screen the kind of gritty-city, late-’70s mood and colorful characters the author was famous for, Schechter risks sacrificing the snap and sizzle of glitzier, gamer efforts like “Get Shorty” or “Jackie Brown.” (In this movie, street thugs Louis and Ordell are younger versions of the De Niro and Samuel L. Jackson characters in “Jackie Brown.”)

Despite its sluggish intervals, “Life of Crime” satisfies in the end, just when you fear it’ll peter out. Which is the sort of trick Leonard would pull.