Review on Enhance Performance with Bosch 13613 OE Fitment Wideband Oxygen Sensor for Toyota Vehicles: Tacoma, Tundra, 4Runner (2000-2004) by Randy Butler

I bought both O2 sensors for my sons 2004 Tacoma 3.4L 4x4 which showed code P0420 for the catalytic converter system. I made sure there were no intake or vacuum leaks, tuned it, replaced the MAP sensor, cleaned the IAC, reset the light and it came on again. The catalytic converters and O2 sensors had just been replaced so I was looking for something else. Eventually I had to go back to see what O2 sensor part numbers were installed. After doing a lot of research on O2 sensors I came to the conclusion that the wrong sensors were fitted and found that Bosch has been making O2 sensors since the beginning. I read online a white paper written by the GVMT agency and compared several o2 sensors and Bosch proved to be the most reliable and efficient. I don't normally buy anything other than Toyota parts, but I was so impressed with Bosch that I decided to give them a try. I installed both sensors about 2 months ago (highly recommend replacing both at the same time) and haven't had a single problem. The DTC is gone and it runs like a champ. Do your own research but I would recommend it to anyone.