What used to be their best weapon has mostly been firing blanks for the last month or so.
And while they didn't need it much to sweep the Tampa Bay Lightning in the first round of NHL playoffs, it could come in awfully handy when they face the Boston Bruins in an Eastern Conference semifinal later this week.
The Canadiens went 0-for-23 over the final eight regular season games with the man advantage and scored on only two of 13 chances against the Lightning, although one was Max Pacioretty's series-clinching goal with 43 seconds left in Game 4 in Montreal.
It has got to where they don't talk about scoring goals so much as building "momentum" off the power play.
"We worked on the power play (Monday) and we'll work on it more," coach Michel Therrien said this week. "We want to create momentum on the power play and we're working with that in mind."
The Canadiens have spent a lot of time in practice over the past month trying to find answers.
Early in the season, they were scoring regularly until opponents started keying on P.K. Subban's big point shot. Since then, the Canadiens have had trouble finding a winning formula.
They will need it to keep the bigger, more physical Bruins honest and to match the Boston power play, which went 6-for-16 in a five-game win over the Detroit Red Wings in the opening round.
The Bruins used to labour on the power play. They beat Montreal in seven games in a 2011 first round series despite going 0-for-23 with the man advantage.
But that was before they picked up slick point man Torey Krug, which allowed them to move towering Zdeno Chara into a much more effective position in front of the opposing team's net.
Subban looks to the 2011 Bruins as proof that a team can win even if the power play is struggling.
"The year they won the Cup, I don't think that had many power play goals," he said. "The power play is one thing, but I think the most important thing is generating momentum on a power play.
"You're not always going to score, especially when you play a team with a good penalty kill. But you try to create opportunities and generate momentum and really grind down their forwards and defence."
They hope to catch fire against the Bruins. In the first round, there were times they had dazzling puck movement, and other times when they looked like marionettes following a choreographed routine.
It may just be taking more time than expected for trade deadline acquisition Thomas Vanek to make his mark on the first power play unit with Pacioretty and centre David Desharnais.
Vanek has had a big impact on their even-strength play, and facing Boston may be just what he needs to help the power play get going as well. The Austrian has 30 goals and 62 points in 55 career regular-season games against the Bruins, most while he played for the Buffalo Sabres.
Penalty killing is also a concern.
The Canadiens were fourth best in the NHL this season with an 85.1-per-cent kill rate, but gave up two goals on only seven chances to Tampa Bay (71.4 per cent). Boston killed 90 per cent of Detroit's advantages.
The penalty killing units should be bolstered by the return of Travis Moen from a concussion. The left-winger missed the last nine games of the regular season and the first round of playoffs after he was injured in a March 24 game against the Bruins.
He has been skating on the fourth line with Daniel Briere and Dale Weise. Rookie Michael Bournival played well in that spot in the first round.
"I haven't decided on our lineup," said Therrien. "To prepare Travis, I've got to have him practice with players who might have a chance to play. But he's a guy with experience. He's a big body and he kills penalties."
The Canadiens will face the Bruins for a record 34th time in the post-season. Montreal has won 24 series, but the Bruins have won seven of the last 11, including the last two.