The P1151 code will not stop your car from running anyway. It will continue to drive without any noticable change in behavior except for slightly higher fuel consumption. Left unrepaired for too long (months), however, it will increase chances of cat converter failure.
The "sputtering" as you called it, it not likely related to this sensor. That will have to be addressed separately. Common causes are plugs, wires, or restricted fuel delivery.
Steve
