Performed clean and check on gas furnace customer mentions unit was making a noise when system shut down cycled furnace performed combustion analysis tested and inspected all electrical components and controls found a weak blower capacitor cleaned flame sensor noted that pan on the bottom of the blower compartment had been replaced but not secured causing some of the metal to knock against the cabinet. Fastened panning to the furnace and replaced the blower capacitor all operations are normal at this time.