Kris Boyd made a scoring return for Rangers but could not prevent Paul Le Guen's beleaguered side dropping another two points.
Kris Boyd scored on his return for Rangers
Richard Brittain hammered St Mirren into an early lead in a game from which they thoroughly deserved a point.
Boyd headed the equaliser five minutes later from a Charlie Adam corner.
But Brittain, Mark Corcoran and Simon Lappin came close to adding to the Buddies' tally, while Boyd and Nacho Novo squandered chances for Rangers.
Boyd had started for Rangers after recovering from an ankle injury, with misfiring striker Filip Sebo returning to the bench.
Goalkeeper Tony Bullock returned in goal for St Mirren after recovering from a virus, while Ian Maxwell and Alan Reid replaced Kevin McGowne and John Sutton.
Mark Corcoran and Simon Lappin had already fired shots towards the Rangers goal before St Mirren took the lead after 13 minutes. Corcoran's cut-back found Brittain on the edge of the box and the midfielders fired home a thunderous shot.
But Rangers were on level terms five minutes later when Boyd met a Charlie Adam corner and bulleted home the header from six yards.
Boyd threatened again when he had a shot saved by the legs of Tony Bullock, but the Buddies goalkeeper was rarely tested in the first half.
Richard Brittain put St Mirren ahead at Ibrox
And Brittain had another sight of goal in the 44th minute, but his left-footed shot cleared the bar.
The woodwork denied Rangers shortly before the break when Adam's free-kick crashed off the crossbar.
There was a controversial start to the second half when Novo went to ground under pressure from Kirk Broadfoot, but referee Eddie Smith ignored the penalty pleas.
St Mirren then almost reclaimed their lead when Corcoran was allowed to run from the middle of the park and into the box before firing inches wide of the post.
Novo missed a decent chance to put Rangers ahead when his effort was also off target.
Rangers, with Chris Burke replacing Adam, pushed forward in the final minutes in the desperate hope they could still snatch the three points.
But the Buddies held on for a well-deserved point as the crisis deepened at Rangers.
Rangers: McGregor, Hutton, Hemdani, Svensson, Papac, Sionko, Ferguson, Clement, Adam (Burke 59), Novo, Kris Boyd.
Subs Not Used: Klos, Rae, Murray, Sebo, Stanger, Lennon.
Goal: Kris Boyd 19.
St Mirren: Bullock, van Zanten, Millen, Broadfoot, Reid, Murray (McKenna 46), Brittain, Brady, Maxwell, Lappin, Corcoran (Gemmill 90).
Subs Not Used: Smith, Potter, Sutton, McCay, McGinn.
Goal: Brittain 14.
Ref: E Smith