I have a Carrier furnace, Mod #58GS100-BA. When the thermostat calls for heat, the ignitor sparks, the pilot lights, and the burners come on like normal. But after the burners are on for a few seconds, they go out. After a few more seconds, the burners come on , then die out again. This on-again, off-again cycle continues for as long as there is a call for heat on the thermostat, with the pilot staying on the whole time. There's no wiring diagram, so any help anyone could offer would be appreciated.