My Trane furnace is shuting down just as it fires up. It's an XE80 Trane model. The burners will ignite, then after about 10 seconds or so, they will just go out. Then, after about 20 seconds they will re-ignite and go out again just like before. Finally, after about the 3rd or 4th time, the fan blower will kick on and just blow cold air because the burners went out. Any suggestions/comments/advice would be greatly appreciated.