Bafetimbi Gomis thought he had earned a draw for Swansea when he equalized in the 90th minute with a powerful rising shot that beat Joe Hart at his near post from a difficult angle.But City recovered as Toure created the winner in stoppage time with a shot that took a deflection off teammate Kelechi Iheanacho to put the host provisionally back atop the standings, ahead of Leicester on goal difference. Iheanacho was credited with the goal after the ball hit his back and changed direction and looped into the net.
Swansea, playing its first game since manager Garry Monk was fired, is 15th on 14 points from 16 games.
Until the eventful ending, it had been a drab game played in pouring rain, with Wilfried Bony giving City the lead in the 26th minute with a header against his former team.
Swansea was the better team in the second half, though, with Hart preventing the visitors from equalizing sooner.
Caretaker boss Alan Curtis and the rest of the bench leapt to their feet as Gomis finally broke through but the joy didn't last long as Toure's fortuitous strike went over Lukasz Fabianksi.
City, having named Kevin De Bruyne on the bench, were sluggish throughout even though they controlled the majority of possession.
It took City 14 minutes to muster an attempt on goal and Bony's tame shot was easily dealt with by Fabianski.
Jesus Navas went close midway through the half as he cut inside to shoot on his left foot. His strike was deflected wide but he picked out an unmarked Bony with his cross from the resulting corner and the Ivorian powered in a header.
It was the fourth time in succession he had scored in this fixture, with two appearances for each club, but he chose not to celebrate, instead pointing to the rain-filled sky.
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