Where is the fuel shut off switch in a 2000 Pontiac Montana van?

There isn't a readily accessible, manually operated fuel shut-off switch in a 2000 Pontiac Montana van like you might find in some older vehicles. Modern fuel systems rely on electronic controls and safety features. To stop the fuel flow, you'd need to either turn off the ignition or disconnect the fuel pump relay (which requires some mechanical knowledge and isn't recommended unless you're experienced).