the fouler should work, and its cheap. so if the rear o2 code has not shown its self let it go till it does.

and that code is for the up stream o2, http://www.obd-codes.com/p0141 its basically saying the heater in the o2 is not working. this is the o2 thats blocking the spark plug on the back of the engine. you need a o2 socket to remove it.