My furnace is turning on every minute, running for a minute, and then shutting down. The air that is blowing out is simply lukewarm, and is not coming out of every vent. I have the thermostat set at 72, but it isn't above 66 in the house.

It's a Trane gas furnace. Any suggestions?

Thanks a lot for your help.

Yes here is a suggestion. Post the exact model number and a bit more info on what the problem is and what the furnace actually does.