I have a York Diamond 80 furnace which I have replaced flame sensor on and I am still having trouble with the furnace lighting or staying lit. It's random when it decides to light or not. Two years ago they came through my neighborhood and replaced the high pressure gas lines. Is it possible that there could be bebrie in the gas valve even with a dirt leg in piping prior to the piping entering the valve? I need to get this POS up and running it's December 22 and I'm having the family over for the holidays. Any help or possible ideas to fix this issue wuold be greatly appriciated! Thanks