Goodman Furnace Burner issue
Hello. I have a Goodman GMP100 furnace that is having some issue with burner flame. When the flames come out from the 4 tubes, the flames from 2 left tubes go out immediately and only the right 2 tubes have flames. This last for about 2 to 3 seconds and then flames from all tubes goes out completely and whole cycle starts all over again. Sometimes, the flames from the last 2 tubes goes out and then come back immediately and stays lit. In this case, the system works properly. The problem is that chance of this happening is only about 50% time.
Does anyone know why the flames from the left 2 tubes may go out? Do I need to clean these tubes periodically? Can it be flame sensor rod? If it is, then how can right 2 tubes have flames on?
Any help would be highly appreciated.
Thanks in advance.