Grade: C-

The secret to a successful action comedy is balance: neither half of the equation should overwhelm the other. In Michael Dowse’s “Stuber,” however, the violence is so graphic and unremitting that the lighter elements get swamped, even thought the inevitable mismatched buddies exhibit some chemistry.

The picture opens with a sequence that exemplifies the problem. Cop Vic Manning (beefy ex-wrestler Dave Baustista) and his partner Sara Morris (Karen Gillan) confront drug smuggler Oka Teijo (Iko Uwais) and his crew in a high-rise hotel. A long, brutal, mirthless melee results, and Morris predictably winds up dead. Now Vic has a partner to avenge.

This whole set-up demonstrates that to Dowse, at least, it’s the action stuff that really matters—and he, cinematographer Bobby Shore and editor Jonathan Schwartz go whole hog to show their proficiency at it. To a large extent they succeed, here and elsewhere; but there are no laughs to be had.

In addition to wanting revenge, Vic also has a serious vision problem that requires surgery. He has the operation done, unfortunately on the very day that his daughter Nicole (Natalie Morales), a sculptor, is having a gallery opening, and so she puts an app on his phone so that he can summon a drive to get there despite his diminished eyesight.

Of course, he thereupon gets a call from his snitch Leon (Amin Joseph) that Teijo is moving a big shipment that very day. Vic’s attempt to drive himself to Leon is a disaster, so he calls Uber, and who should appear but Stu (Kumail Nanjiani), who arrives in his little electric car. Stu works a regular job at a big-box sports store, where his insufferable boss (Jimmy Tatro, who seems born to the role) ridicules him with the nickname Stuber because of his second gig.

Stu’s a sad sack, who—as a montage shows us—has had to deal with lots of troublesome riders, and his ratings are going down. He’s also pining away for Becca (Betty Gilpin), his “best friend,” whose idea for a new fitness center he’s financing beyond his means. In a running series of phone conversations, she tells him that she’s broken up with her boyfriend and asks him to come over. Thinking this his big chance at romance, he’s desperate to wind up the night and get over to her place.

Naturally that won’t happen, since he’ll be stuck not only driving the nearly blind Vic around as the big fellow follows clue after clue to locate Teijo, but being drawn into the mayhem that erupts at every stop along the way. (Vic’s relentless pursuit is unauthorized, of course, per his captain, played by Mira Sorvino.) There’s also a side trip to the sports store for firepower, where the two have a knock-down, drag-out brawl of their own, as well as another to Nicole’s show, where Stu gets to know her a bit.

It all comes down to a final face-off with Teijo, but not before the revelation of some malfeasance in the police department. In a script already rife with clichés, that’s perhaps the worst of all—though the coda, which seems primed to lead to a sequel, is no prize.

The comic sparkplug in the movie is definitely Nanjiani, who follows up his unexpected multi-talent work in “The Big Sick” with another winningly underdog turn. One suspects that many of his lines, delivered in quiet, understated tones that threaten to be drowned out by the cacophony surrounding him, were improvised, but even if that suggestion does an injustice to scripter Tripper Clancy, Nanjiani’s manner effectively convinces you of their spontaneity.

Bautista is hardly a finished actor—he exhibits the stiffness of a young Schwarzenegger (and even the older one). But he certainly has pugnacity, and a certain charm—even though “Guardians of the Galaxy” shows it off to better effect.

Nobody else in the cast is especially noteworthy; Uwais exhibits his athletic prowess, but his sneering performance is tedious, while both Morales and Sorvino are pretty one-note, and Gilpin is similarly stuck doing repetitive shtick. Tatro, a You Tube personality, is, as mentioned above, a very convincing creep.

There’s a fairly nice, subdued performance by Scott Lawrence as a veterinarian to whose office Vic and Stu take a wounded thug to be stitched up. But the sequence turns into yet another bloodbath, and though the makers try to inject a farcical element into it, it remains more likely to elicit cringes than chuckles; and then they add a particularly mean coda to it.

Some will no doubt argue that the movie represents product placement at its worst, and they’re probably right. But that’s the least of the picture’s problems. At the close of the trip “Stuber” has so bludgeoned you with heavy-duty action that the fun it’s supposed to have provided has receded far in the rear-view mirror.