uplander won’t run more than 30 seconds with Map sensor plugged in and has open circuit code P0641
Will it run for more than 30 seconds with the MAP disconnected? If so, I’d suspect the map sensor wiring has been damaged, the sensor itself if damaged. If it still dies in 30 seconds, it may be another sensor or the ECM.
More than the MAP sensor is attached to the 5 volt supply that can trigger the P0641 code, however as can damaged wires.