Jason Pominville scored at 9:38 of the first period to help the Sabres rebound from two straight losses.
It was Miller's third career playoff shutout and second of the series after he stopped 35 shots in Buffalo's 1-0 victory in Game 1.
Miller's best stops came in the final 9 minutes. First, there was his glove save in stopping Danny Briere, who was set up alone in front. A few minutes later, Miller reached back with his stick to prevent Mike Richards from slipping a shot into an open left side.
The series shifts to Philadelphia for Game 5 on Friday night.
Flyers goalie Brian Boucher was sharp, too, in stopping 28 shots.
Boucher has allowed only four goals on 87 shots since replacing rookie Sergei Bobrovsky in the first period of Philadelphia's 5-4 victory in Game 2 on Saturday.
The only goal Boucher allowed Wednesday was through no fault of his as Pominville completed a nifty tic-tac-toe passing play in front of the net.
Tyler Ennis started it from the end boards with a blind backhand pass to Rob Niedermayer to create a 2-on-1. Niedermayer quickly fed a pass through the crease to Pominville, who redirected it in the open right side.
Miller was the star in becoming the third Sabres goalie to register two shutouts in one playoff series - and first since Dominik Hasek had two against New Jersey in 1994.
Despite Miller's series-opening shutout, fans had begun criticizing the goalie after he struggled in allowing eight goals on 59 shots. Miller answered with a solid performance while bailing out his teammates, who committed numerous turnovers in their own zone.
The soldout crowd was on its feet cheering Miller's best stop with 8:50 left. That's when the Sabres failed to clear their own zone and Briere was set up alone in front of the net. Briere, the former Sabres co-captain, spun around, settled the puck, avoided the goalie's poke check and then snapped off a solid shot only to be robbed by Miller's glove.
Miller was just as sharp some 4 minutes later by reaching back with his stick to prevent Richards from slipping in a shot into the open left side following a scramble in front. That stop got the crowd chanting "Ry-an Mil-ler! Ry-an Mil-ler!"
Tyler Myers contributed with a key save 13 minutes into the game with James van Riemsdyk set up in the slot and facing an open side. Myers slid down to get a piece of the shot to deflect it over the net.
Van Riemsdyk was foiled by Miller on numerous occasions, including three chances during a 10 second span midway through the second period. Miller first held his ground as van Riemsdyk got two whacks at the puck alone in front. Van Riemsdyk then got another chance when he stripped Niedermayer of the puck behind the Buffalo net but was stopped by Miller while attempting to sneak a shot inside the right post.
The Flyers lost Carter, who did not return after hurting his right knee following a collision with Myers in front of the Buffalo net with 2:20 left in the first period. Both players were looking the other way when Carter was cutting through the crease.
Myers was shaken up, too, after Carter's shoulder caught him across the job. Myers, however, returned for the start of the second period and played a regular shift.
The chippy play that has dominated much of the series with several hard hits and shoving matches. Richards was issued a 5-minute major for elbowing in the final seconds of the second period when he felled Sabres agitator Patrick Kaleta in the face while bracing to be hit in front of the Buffalo bench.
Buffalo failed to take advantage, managing just two shots during the power play. Richards eagerly jumped up and down in the box as his penalty was expiring.
Briere showed his frustration behind the play in the second period, when he pulled the stick out of defenseman Mike Weber's hands and tossed it into the Sabres net.
The game ended with a shoving match. As both teams left the ice, Flyers coach Peter Laviolette slammed the bench door before heading to the locker room.
NOTES: The teams had gone 0 of 5 when enjoying a two-man advantage in the first three games. Philadelphia failed to score on three opportunities spanning a combined 2:34, while the Sabres were blanked twice over 1:37. ... With four assists, Sabres D Marc-Andre Gragnani is the team's first rookie to have points in each of his first three career playoff games since Richard Smehlik in 1993. ... The team that has scored first has gone on to win in all four games in the series.
