What is wrong near my furnace??? I have an grease furnace, I have the temp set to 72,...

I have an grease furnace, I have the temp set to 72, furnace kick on and off intermittantly short ever reaching 72, then at least possible three times a week the honeywell ignitor will shut down to where I enjoy to press the reset button but it never gets up to proper temp when it is on. I own a regular dial honeywell thermostat (t87). H E L P!!!
Answers:    flame sensor is dirty. clean it.
It sounds approaching a sensor in the burn chamber that have gone bad. A section like that requires a cert. tech. to repair. Sorry.