I have a Goodman GMPN060-3 gas furnace. My ignitor will glow and ignite the burner but will go out in just a few seconds. I have replaced the ignitor but still have the same problem.
The furnace will try to ignite three times before shutting down. Sometimes it will ignite and continue burning on the second or third try. Sometimes it will burn on the first try. There is nothing consistent about this problem. The bad part is waking up in the morning to a cold house. Any suggestions on how to solve this problem?

Clean the flame sensor with fine sand paper or steel wool.

Do as hvac1000 says, clean the flame senser, and you will most likely be back in constant heat. If you need more help locating the flame senser, come on back and we will try to help.

I have the same problem and it was Not the flame sensor or pressure switch and there are no faults being shown on main board. Please Help!