My gas furnace seems to run through the cycle to ignition but has intermittent problems running throught the end of the cycle. Sometimes it runs through the entire cycle fine and sometimes it doesn't. At the times it has problems at ignition, it appears to ignite, but can't seem to hold the flame--which seems to stutter and then goes out . The heater then seems to reset and then run through the cycle again in a few seconds and runs through the entire cycle.

It is an 8 year old Payne heater, and I had the whole thing checked and cleaned in mid-October. The tech who checked it adjusted something in the airflow because it seemed to have some difficulty getting full ignition (it sounded like the flame kind of stuttered before it caught completely).

Today it tried cycling twice and never ignited at all. The led light was flashing. I turned the thermostat up a couple of degrees, and after a minute or so it cycled perfectly. It seems to be operating fine now, and the led is no longer flashing.

I am concerned that this is an ongoing, intermittent problem that could get worse. Any ideas on what the cause could be--could it be related to the thermostat?

Your thermocouple could be dirty from soot or out of alignment.

The flame sensor maybe dirty. Clean it with sandpaper or steel wool. For more help, see the sticky at http://www.askmehelpdesk.com/heating-air-conditioning/heating-cooling-maintenance-repair-troubleshooting-frequently-asked-questions-58313.html