The Pistons have won eight of their last nine games against the Sixers.
Willie Green scored 16 points, Andre Iguodala had 15 and Lou Williams 13 for the slumping Sixers. Philadelphia has lost 10 of 12 and what few fans turned out left in droves in the fourth.
Samuel Dalembert grabbed 13 rebounds and Reggie Evans had 11 boards for the Sixers.
Tayshaun Prince scored 16 points, one of three Pistons in double-digit scoring. The Pistons went only 6-for-21 from the floor in the fourth, allowing the Sixers a bit of hope they could hang with one of the elite teams in the East.
Neither team scored in the first 2 minutes of the fourth until Williams made a free throw that sliced the deficit to 70-64.
The Pistons missed six straight shots to open the fourth and scored only four points over the first 8 minutes.
The Sixers couldn't take advantage, with Iguodala missing wide open looks on a pair of jumpers that could have jolted them right back into a rather lethargic game.
Wallace finally provided the Pistons with a dose of offense with two free throws and then a 3-pointer that made it 79-67.
Green answered with his own 3 and Williams nailed a fadeaway that pulled the Sixers within seven with 3:54 left.
But that was about all the scoring for either team.
The Pistons have shown over the last few years that they could easily beat the Sixers. A convincing win over the rebuilding Sixers might have been exactly what they needed to get back to playing like the team that ripped off an 11-game winning streak earlier this year. Instead, the Pistons led 50-41 at halftime and only took a seven-point lead into the fourth.
Notes: LHP J.C Romero, OF Shane Victorino and NL MVP Jimmy Rollins of the NL East champion Phillies were honored at the game. Rollins and Iguodala swapped jerseys before the game and Rollins won a halftime shootout between the three Phillies. Rollins, who called the Phillies the team to beat last year and predicted 100 wins this season, enjoys the target that comes with being the defending champs. "I don't see it being any more on us than it was last year," he said. "If we're the front-runners, that's fine with me."
