Solutions for too much compression

years ago i was working at a gas station when a customer drove up complaining of an engine knock. mechanic came out . listened to the engine. started to pour atf down the carb until the knock quit. seems there was enough carbon build up that it was actually hitting the head. Point is , after 17 years. is it possible that stop and go driving has allowed carbon build up to the point where you get 180lbs in a 9.5 -1 motor???