Manucho gave Angola the lead with a low strike in the fifth minute after poor defending, before Mohamed Ahmed Bashir headed the equalizer in the 33rd.
Manucho put Angola back in front with a 50th-minute penalty, but Ahmed Bashir scored again in the 73rd to level for the second time for Sudan.
The result leaves Angola well placed to progress with four points from two games, while Sudan has one point and must beat Burkina Faso in its last match to have any chance of qualifying.
''We will keep fighting. We have now four points and our objective as always is to try to do better,'' Angola coach Lito Vidigal said.
Later, Burkina Faso faced pre-tournament favorite Ivory Coast in the other Group B match at the 15,000-plus Nuevo Estadio de Malabo.
Sudan coach Mohamed Abdallah made two changes from the 1-0 loss against Ivory Coast, preferring Akram Elhadi Salim in goal and bringing in midfielder Mohamed Tahir.
Vidigal named an unchanged lineup from the 2-1 win against Burkina Faso, resisting the temptation to include former Germany youth international Nando Rafael, who received clearance to play earlier in the week.
Attendance was again disappointing for the match, with a pocket of around 500 Angola fans on the halfway line but thousands of empty seats elsewhere.
Angola's supporters were soon celebrating when their side took the lead thanks to a glaring error from Sudan defender Nagm Eldin Abdalla.
Manucho robbed the ball as the defender tried to turn and advanced into the box to drill a low shot into the corner for his second cup goal.
''I'm trying to minimize the small mistakes of our inexperienced defenders playing against high-quality strikers,'' said Abdallah. ''I think we are improving.''
Sudan was playing a more expansive game than the counterattacking style that frustrated Ivory Coast, and Tahir forced Angola goalkeeper Carlos Fernandes into a diving save in the 18th.
''To survive in this competition you have to win, so we played more offensive'' said Abdallah, whose team was searching for its first away win in the finals since 1963.
The equalizer came soon after when Mudather Eltaib crossed from the right and Ahmed Bashir rose above the defense to send a glancing header just inside the post. That was Sudan's first goal in the finals since 1976.
Djalma had an effort cleared from the goalmouth in the 38th, but Angola had let the initiative slip as halftime arrived.
Vidigal sent Rafael on for his debut in the second half and five minutes into the second period Djalma was tripped in the box by Sudan defender Nazar Hamid for a penalty.
Manucho side-footed the spot kick to the goalkeeper's right to restore Angola's lead.
Yet again however, Angola made the mistake of sitting back and Ahmed Bashir volleyed into the net to level for the second time after Jose Vinguidica failed to clear.
''We made a mistake and Sudan took advantage to score,'' Angola captain Andre Macanga said. ''It's a very fair result. We depend on ourselves, there's still a long way to go in this tournament.''