Miller had 12 points, 12 assists and eight rebounds for the Sixers, who improved to 12-16 and defeated the Heat for the 13th time in the last 15 games in Philadelphia. The Sixers won their second game in a row before starting a six-game road trip beginning Friday night in Sacramento.
Iguodala scored 23, including the winner as time expired, while Miller had 29 in Saturday's 99-97 win at Memphis.
"The experience of Andre Miller really helps us in these situations," Sixers coach Maurice Cheeks said. "He set the tempo. He scored in the first half, and in the second half, he decides whether to score or distribute."
Iguodala shot 10-of-17 and also added seven rebounds.
"We've been talking this last week about finishing our games," Iguodala said.
Dwyane Wade scored 20 of his 27 points in the second half and Ricky Davis added 21 for Miami, which dropped its second in a row on back-to-back nights. The Heat (8-21), who lost 96-82 at Cleveland on Wednesday, fell to 4-12 on the road and remain mired in last place in the Southeast Division. Daequan Cook had 12.
"We just didn't have it," Miami coach Pat Riley said. "We weren't playing hard. We were obviously out of sync."
Philadelphia led by 19 points early in the third quarter before the Heat began to chip away. Miami got within 74-64 when Wade went the length of the court and converted a layup with 0.2 seconds remaining.
The Sixers responded with a pair of 3-pointers by Iguodala and Korver to take a seemingly commanding 80-64 lead.
Miami later went on a 13-2 run, with Wade scoring eight points, to cut the Sixers' advantage to 84-81 with 5:08 remaining.
Philadelphia came right back with six straight points, two baskets by Samuel Dalembert and a dunk by Iguodala, for a 90-81 advantage.
The Sixers sealed the victory when Williams drove around Wade and threw down a one-handed dunk over Udonis Haslem for a 93-81 lead with 1:49 left.
"It's tough to lose," Wade said. "But it's tougher to be the worst team in the Eastern Conference. You don't know what you're going to see from one night to the next."
Even though Dalembert picked up two fouls in the first 1:27, the Sixers later built a 21-point advantage in the second quarter and cruised to a 55-38 lead at halftime.
The Sixers quickly jumped ahead thanks to hot shooting by Iguodala, who had 19 points on 7-of-11 shooting, and steady play by Miller, who added 12 points and six assists.
Miami C Shaquille O'Neal had 10 rebounds, giving him 11,606 in his career. O'Neal is two shy of passing Patrick Ewing, who is currently 22nd all-time with 11,607. ... Sixers G Willie Green (groin) was replaced in the starting lineup by Rodney Carney. ... Miami G Chris Quinn (ankle) missed his third consecutive game while G Jason Williams was held out because of a sore knee. ... Sixers C Calvin Booth had four of his season-high five blocked shots in the first quarter. Booth entered the game with two blocks all season. ... Miami misfired on all six 3-pointers in the first half and finished 1-for-13.