York system starts intermittently

Hi All, I have a 14 year old York system that will only start occasionally. Actually, I'm starting to believe it is haunted, and only starts when it feels like it. The unit is located in the attic, and each time it attempts to start it sounds normal, but then shuts back down before it can start blowing heat. I first noticed this a couple of weeks ago, but when I flipped the power to the furnace off and back on again it fired back up like normal. This problem has been happening every couple of days, but pulling the batteries from the thermostat would quickly rectify the problem. The problem suddenly became much worse two days ago, and now I can only get it to start once or twice per day. I have climbed into the attic and watched as the ignitor fires and the gas is ignited, it then sits there for a few seconds and then shuts back down. It kind of seems like the blower just doesn't start. However, the fan will start when switched on at the thermostat. Here's the quick list of things I have tested and/or been able to confirm: