I have a Atwood afsd20127. The sail switch fouled and cleaned it up. After starting furnace back up it now runs about 10

Robert, This is a new 4 month old unit. The initial problem was thermostat would start blower and shutdown 30 seconds later without trying to light. A fouled sail switch was the issue. I cleaned, reinstalled unit and tired of up. It can find but burner would cycle of after several minutes and relight 90 seconds later with the blower running all the time. This led me to change the high limit cutout and it is doing the same thing with a new one. Further research found the anticipater pushed low off scale. Atwood stated they set them all at 1.0. The valve is a 0.43. I am running it at 0.55 and with current temps is is meeting demand without short cycling. I think for now the warmer temps and shorter demand cycles is covering the problem because it can find for 4 months with the anticipater set low as possible. Some points to ponder. 1) There is a wad of dust bunny causing low air flow causing an actual low flow condition. 2) A possible had cool on gas valve that is expanding after heating causing an open until clam out and fools down 3) sail switch is intermittent but I don't think since each failed cycle times the same down to the seconds. Is there possibly something on the board causing this problem. I have a new board. I was waiting on warmer weather to remove the unit and bench test it with instruments on each safety to see what is actually causing the situation. Any ideas!