In a nutshell what I do is to pop off the engine cover, locate the sensor. It's located on the highest spot in the intake manifold, slightly on the drivers side of center. Unplug the sensor then unbolt it. Mine has 2 torx screws. I have read that many have only one retaining screw. Bean counting or lazy assembly IDK. Pull the sensor up and out. I had to wiggle mine a bit as the O ring seal is a little snug. Reverse the process to install the 3 BAR. I labeled mine as they look alike and I did not want to mix them up. When done with that get in the car and go through your tune install procedure. With mine at the end of the tune install, my instructions are to turn off the ignition, wait ten seconds then start the car. In order to follow my directions to the letter I needed to swap out the sensor before loading the tune. Maybe with another tuner, the needed steps might change slightly. If no codes are thrown after the startup, you are golden.
