I recently had a prob. w/my High Eff. Trane gas-fired furnace. Pilot would light,, Electronic Ignition sensed the flame, and ignited the blower. Blower would operate and fan would come on. But, the pilot and burner would shut down, and ultimately the fan went off. It would then recycle in the same manner, but wouldn't stay on. It turned out the PVC pipes --Fresh air intake, and /or Combustion air vent were sloped incorrectly and was partially filled w/condensate--water. The Induction motor was sensing the blockage, and shutting the system off. It would then recycle again, and again, etc..
I hope this may be of help.