The Light Blues took the lead through John Crawford's own-goal just before the break, but substitute David Gray claimed an 89th minute leveller with a superb long-range strike.
Rangers are still 20 points clear at the top of the Irn-Bru Third Division, but manager McCoist vented his anger at the players after they were jeered off the pitch.
"I was booing myself. I'm probably as angry as I've ever been as manager with that performance," said McCoist.
"I'm not even interested in the wonder goal with a couple of minutes to go. You could see it coming, you could absolutely see it coming.
"Our overall performance was not good enough and our standard of finishing was probably worse."
McCoist insists his players will have a bleak future at the club if they produce another unacceptable display.
When asked if the Gers had been guilty of a lapse of concentration, he said: "I don't know. But I tell you what, they better switch on kind of quick or they will be completely switched off.
"What I'm saying is, that level of performance can't, and won't, be tolerated.
"It seems a bit bizarre saying that when they've only had two draws in 14 games but, at the same time, the supporters deserve a better level of performance than what they got today."
McCoist refused to use the absence of injured skipper Lee McCulloch as an excuse for the draw.
"It's too simple to say that," he said. "That team we put out there today, regardless of the result, should be performing at a higher standard."