"Is it all ashes, or is there still a spark?" a miserable Jack Lemmon asks himself soon after entering "Buddy Buddy," a comedic atrocity from Billy Wilder. Lemmon's character, a schnooky network censor named Victor Clooney, is preoccupied with a wrecked marriage, wife Paula Prentiss having abandoned him for sex therapist Klaus Kinski, but both the marriage and the movie are finished before this melancholy question is spoken.

Never a promising project, "Buddy Buddy" was adapted by Wilder and co-writer I.A.L. Diamond from a disagreeable French farce, "L'emmerdeur." Imported about five years ago under the relatively subdued title "A Pain in the A--," the French movie is one of the December offerings on Cinemax, the supplementary Home Box Office channel. Its screenwriter, Francis Veber, and director, Edouard Molinaro, later hit the jackpot with "La Cage aux Folles," but "Pain" was a deadpan insult, compromised from the outset by a premise that defied amusing development.

Lino Ventura played a mob assassin whose efforts to carry out his contract were repeatedly upset by Jacques Brel, a suicidal pest registered in the adjacent hotel room. Walter Matthau and Lemmon, who co-starred in two previous Wilder movies, "The Fortune Cookie" (which brought Matthau an Oscar) and "The Front Page," assume the nominally Americanized roles of slow-burning killer and interfering stupe.

The principal location is Riverside, Calif., where the killer, called Trabucco and portrayed by Matthau as a kind of Runyonesque wooden Indian, is staking out the last of three victims, fellow mobsters who have agreed to turn state's evidence. Trabucco's plan is to plug Victim Three with a high-powered rifle from the window of his hotel room, located across the street from the courthouse. Lemmon's pathetic Clooney, the guest next door, creates an inconvenient commotion when he fails at a suicide attempt in the bathroom. Hoping to protect his timetable and vantage point, the killer ends up playing exasperated nursemaid and the suicide confuses this solicitude with budding friendship.

The opening sequence is peculiarly slack. Matthau, disguised as a mailman, is supposed to knock off his first victim by delivering a letter bomb. Unfortunately, it's the movie that seems to bomb from Step One, since the explosive package resembles a defective Roman candle. The plot is wobbly after one scene, because it's difficult to accept the fiction that Matthau has murdered anyone with that inept fireworks display. Unable to show what he needs to in the first scene, Wilder blunders in a complementary senile fashion in the second scene by lingering over the self-evident. When it's readily apparent that another victim has been poisoned by drinking from a tainted milk bottle, Wilder finds it necessary to add an explanatory line and then prolong a kicker, which shows Matthau disguised as a milkman, driving a truck with the slogan "Feel better, live longer" printed on the back. You get it all right -- Wilder holds each shot as if he were directing for a remedial reading class -- but it's not worth getting.

The awful thing about "Buddy Buddy" is that it forces you to acknowledge how depleted Billy Wilder's comic resources have become. For example, there's a disillusioning predictability about a comedy sequence which depicts Lemmon, bound and gagged by Matthau to keep him quiet, being blithely ignored by the maid -- a vaudeville Mexican-American yet. You know the moment she puts key to lock that her bit will consist of ignoring Lemmon's plight. You can also anticipate the sort of lines Wilder and Diamond entrust to her. Prattling about her family's catering business to the frantic occupant, she remarks, "We're in the Yellow Pages under Tijuana Gourmet."

It's even painful looking at Matthau and Lemmon in repose, because the cinematography abuses them. There's a long close-up of Matthau behind the wheel of a car in which you fear he's being doubled by a wax mummy. The costars don't so much match talents as unappetizing skin tones, Matthau's complexion suggesting maybe stale toast as opposed to Lemmon's sickly baby shrimp.

"Buddy, Buddy " is deadly-deadly.