If it's only shutting off in idle or low RPMs it's most likely a vacuum issue, map sensor is a part of that system and if you already replaced that then check all vacuum hoses for cracks/breaks. If you're stalling as you're driving (above 1000 RPMs, take of your intake manifold (just the rubber hose part) and see if it's not torn in half on the bottom, that would definitely cause an intermittent stalling problem. Every Aveo I had, had the intake torn in half when i bought it, can't see it from the top though.