American Standard freedom 90 blows cold and red light flashes 6 times. Does this mean the igniter has gone out?

Locate the service label with codes & instructions. It may be on the inside of the front/blower panel, or on the circuit board housing. If code 6 is limit-related, your furnace may be overheating. Repeated cycling of the limit switch may cause it to stick open. Try tapping the butt of a screwdriver between the terminals to see if it will reset. If normal operation is restored, investigate cause of overheating (clogged filter, etc.).