I have a trance xl 90 furnace. I keep getting lockouts. I replaced my igniter and flame sensor. I get flame on the first of three jets and she shuts down before it reaches the flame sensor on the 3rd jet
probably a gas pressure issue or dirty burner crossover tubes.
best to call for service unless you know how to work with gas - may have to remove manifold to be able to pull the burners.
don't buy any more parts.
I am not in the business of any trade I give advice on. I have non-professional hvac experience + good knowledge of theory. Attempt repairs at your own risk. Never jump out safeties - especially pressure switches - on a furnace for testing with fuel supply on; use a meter. Do not troubleshoot with live line voltage present unless there's no alternative.