The shop tested and diagnosed the rear 02 sensor as being bad, with 100% certainty. They replaced the sensor and unfortunately the code is back with another. Originally I had the P0138 only, now I have P0138 and P0139, so I need to take it back in. Both codes still seem to point to the rear sensor but I am wondering if the forward sensor needs replaced or if I might have a leaking injector.
The car is used by my daughter and we really like this car, but I am very much regretting purchasing it. It' is like I keep paying for the same repairs over and over and never actually get them fixed.