Furnace won't kick on!

[jmw]

For the past 2 weeks the furnace will not turn on unless we turn the thermostat all the way up to 90! It will act like it is starting but then turn off. Then when it turns on it will get up to 80 and then turn off and go back down to 68, any clue what's wrong?

[pcdoctor]

Either Thermostat problems or other things. You may want to have a professional come and look at it. I would recommend calling your gas company.