I have read similar problems here, and have not read a solution.
I have a Trane XB80 furnace (5 years old or so), and recently it started acting very flakey: The ignitor glows bright orange for a moment, gas shoots out the tubes for a few seconds (10 at most) then it clicks off and cool air blows.
I looked at the red flashing light on the control board, and it just flashes continuously and evenly, no groups of four or anything).
Any help (or possibly direct me to a thread with a possible answer)? We really can't afford a big bill right now, but the temperature has hit -25c (that's -13 f), and I am really starting to worry.

Did you try cleaning the flame sensor?

Thank you very much! That's exactly what the problem was!

Where is the flame sensor loacted on the Trane XB80?