2001 Mitsubishi Montero won't hold rpms

I have a 2001 Montero Sport - was driving and then suddenly just died. Waited an hour for it to cool down and then started. Turned over but wouldn't hold rpms so she died immediately. Started in neutral and kept foot on the gas to keep rpms up and it worked, but the minute I let off the gas, she died again.

Any help would be appreciated!

Thank you.