McNamara declared in midweek that he would resign if the Minstermen failed to get a "positive result" from the trip to Braintree, and was just moments away from York's first win in 30 away league games thanks to Simon Heslop's early strike.
But Lee Barnard tucked home an 88th-minute penalty to leave McNamara to ponder his future, with York winless in seven games and just above the drop zone.
The former Celtic player had made his win-or-bust call in the wake of a 6-1 defeat to lowly Guiseley on Tuesday night, and he was indebted to his goalkeeper Kyle Letheren, who saved a 12th-minute Simeon Akinola spot-kick and then made a string of saves before Braintree finally broke through.
Report supplied by the Press Association.
Match ends, Braintree Town 1, York City 1.
Shaun Rooney (York City) is shown the yellow card.
Second Half ends, Braintree Town 1, York City 1.
Goal!  Braintree Town 1, York City 1. Lee Barnard (Braintree Town) converts the penalty with a.
Substitution, Braintree Town. Lee Barnard replaces Oliver Muldoon.
Substitution, Braintree Town. Reece Hall-Johnson replaces Harry Lee.
Substitution, York City. Daniel Nti replaces Richard Brodie.
Chez Isaac (Braintree Town) is shown the yellow card.
Substitution, Braintree Town. Michael Cheek replaces Jack Midson.
Second Half begins Braintree Town 0, York City 1.
First Half ends, Braintree Town 0, York City 1.
Richard Brodie (York City) is shown the yellow card.
Penalty missed! Bad penalty by  (Braintree Town).  should be disappointed.
Goal!  Braintree Town 0, York City 1. Simon Heslop (York City).
First Half begins.
Lineups are announced and players are warming up.
York boss Jackie McNamara was left to decide on his future after watching his side concede a late penalty in their draw at Braintree.