Shutting down so quickly could indicate either a flame sensing issue or a draft inducer pressure issue. If you can follow theduke03's recommendations you may have less testing to do. But since you replaced the flame sensor you could try TEMPORARILY jumping the pressure switch on the inducer blower. If that stops the problem, then check the flue for any type of blockage.
Lastly, if the inducer and flame sensor are good (new), then I would suspect the control board, especially if it's positioned close to the firebox (excessive heat kills electronics).