I’ll be installing my new headers today so I took my old ones off to get ready. One of the O2 sensors came out without too much trouble but of course one was seized. I searched around for a tool but auto sensors are 7/8 in. I did find a 9/16 one on Amazon for $47. I’m calling BS on that. I decided to try and make my own so I took one of my cheapo 9/16 wrenches and using my air cutoff tool cut a slot in the box end for the wire to go through. I got it on the sensor and just for insurance I clamped vice grips in the box end to keep it from spreading. Here is a picture of the tool and by the way it worked like a champ.