This furnace is about 9 years old and has worked flawlessly until recently. The first thing I noticed was the draft motor was continuously running and lack of green LED on ignitor control. Resetthe furnace by cycling power and observed the operation. It went through two cycles just fine. Only thing I noticed was the ignitor continued to fire a few seconds after the burner was lit (figured this is probably normal). When it went to start the third cycle, the ignitor fired, I momentarily saw a flame from the "pilot" tube, then ignition was aborted. Each successive ignition attempt yielded no visible "pilot" flame at all, then it went into lockout. I cycled power again, and this time it started right up. Any clues? Hoping this is a simple fix. Thanks in advance.