[Daryles]

If the furnace turns on and blows, then shuts off, that's classic symptoms of a bad sail switch.
However, since the furnace burner lights then goes out, AND you are not getting much Airflow from the vents, I would suspect an obstruction. The sail switch is doing its job in that case (turning off the furnace). That's what it was designed to check for.
When my furnace kicks on, it blows so hard out the vents it actually lifts the linoleum on the floor a little.

While you are at it, I would remove and clean the burner, tube, wire contacts and everything you can reach.