I have changed the ignitor and the flame sensor. Also I have cleaned all pipes and tubes. The furnace starts and runs for about 15 to 20 seconds and the burners die. It then recycles and does the same thing. This happens three times and then it turns itself off. Before the burners die each time I hear an electronic click as if the control is receiving a message from the flame sensor. The furnace is an 8 year old Goodman model#GMPN848-3 Rev 8.

Check status LED through clear viewer near blower. A little tough to see on this model, as the viewer doesn't line up with LED, & usually wires are in the way. Observe & note pattern of blinks, if any. Look for service legend inside blower access panel.