Turn off the Goodman gas furnace and turn off the gas line that runs to the furnace. Open the maintenance hatch.
Vacuum the area around the burners to remove any dust and dirt build up. Blow compressed air into the burner holes.
Locate the flame sensor, the little metal stick near the pilot light. Rub the flame sensor with steel wool to remove any build up.
Vacuum out the circular blowers, the draft regulator and the flue passages on the Goodman furnace.
Vacuum around the Goodman furnace to prevent more dust from entering. Close the maintenance hatch and turn the gas and power to the furnace back on.