Are you refering to your induced draft fan which is connected to the vent?
If so;
One cause could be of a bad capaciter.
You will need a meter capable of measuring the capacitor.
Do you own a meter?
I just looked up some information on your furnace and you have a 5 year warranty on parts.
If your furnace is less than 5 years old I would get a technician to expedite the warranty process and change the part needed.
Please let me know what happens. Your motor could also be on its way out.
Either way I would like to hear what you find out.
HVAC Technician
EPA issued refrigeration license, College certificate, and 7 years in field.