Only a total of two sensor in this vehicle not 4 as the manual claims.
Also , tried to use a deep O2 socket thru the heat shield and NO GO. Removed the heat shield and easy bolt removal BUT a major pain to remove.
Then with the heat shield to the side tried another O2 socket I had and NO GO.
Used an 7/8" open end wrench since the length fitted better than the 22mm I had. Another pain to remove the O2 sensor. It loosen quickly at first which surprised me, it might have been the KROIL I soaked it with overnight and this morning.
Moved the wrench a few mm at a time due to a tight working area. A stubby wrench would have been handy.
Putting the sensor in was was OK. The hard part again was the heat shield.
LOOKING BACK: A stud that was sticking up that a nut attaches to hold the heat shield. It has a star torque shape on top. I bet it was there to attach a socket to and move the stud down and out of the way for the shield removal. Not sure if I have such a socket.