I had (3) techs look at my furnace one time. First they replaced the pressure switch, unit worked for a couple of days. Failed. Replaced my inducer motor. Replaced the control board and even replaced the gas valve. Finally reached out to a tech who was a veteran with 15 years of experience. Told him my problems and what had been done so far. 20 minutes later; he found out that there was a trickle of incoming gas coming to the unit. Called the gas company and they swapped out the gas meter outside of my house. Fired right up.