Im getting code P0138, bank 1 sensor 2. Theres only two sensors so its obviously the rear one. The CEL has been on since I got the Jeep so im not sure if its affecting my MPGs or not, its sucks gas like a chinese crack whore but its a 5.9 so im not sure if the sensor has much to do with that. Does the rear sensor affect gas milage at all on these?
1998 Jeep Grand Cherokee 5.9 Limited