I have an american standard gas furnace it is 9 yrs old and I just replaced the pressure switch because it was giving me a faulty pressure switch error code and now it goes through the startup procedures the fan comes on glow plug gets bright orange and then I hear a click for the gas to start and fire up the burners and then it just shuts down and goes through the startup procedures again. It will work off and on like this some times it will run for a week sometimes a day then I go out and fiddle with a few wires or let it sit turned off for awhile and then it will ignite the burners. Any ideas?