I'm about ready to ...
After about a week of the furnace functioning largely without a hitch, it's back to doing the same thing: burner lights, runs for a few seconds, and then shuts off.
Called the furnace dude and told him and he sez:
Well, that's different than what it was doing before ... so it must be something else ... we'll be out Monday ...
Ah nooooo ... it isn't really different than what it was doing before ...
(Sometimes the burners would fail to light at all ... but that was less prevalent than than the furnace lighting and then going out after a couple of seconds)
Fortunately, I managed to get the wood stove plumbed into the duct work of the HVAC system of the house ... so it's scavenging more heat off the stove ... even when the fan on the wood burner isn't running.
Seems to me it's either:
1. Another defective gas valve ...
or ...
2. Gas valve was never a problem to begin with, and it's some other component whose faulty operation is intermittent ...
Of course, it could be a combo deal ...