Review on Enhanced Denso 234-9120 Air-Fuel Ratio Oxygen Sensor by Todd Lowry

I have a Legacy GT 05 station wagon 5-speed. My car constantly ran very poor or rich with no intermediate stages and stuttered quite a bit between 2-3k rpm and was a bit rough at idle. Installing this for the old sensor upstream immediately solved all the issues I've had with my machine since I bought it in December 2018. Now the car works like a dream! at the same time for a rather dramatic change in the handling of your car. My car is much more fuel efficient and runs smoothly all the time. I would also recommend disconnecting the negative battery before doing any of this (all three can take a couple of hours) so when you reconnect the battery and start the car the ECU can relearn how to idle and whatnot.