Actually, I tried your way first as it is intuitive and doesn't require a special tool. Went to the trouble of buying a new 22mm wrench at Sears. However, in this case, the space around the sensor was't large enough for the open end to fit and the 6-pt box end would fit over the sensor, but positioned without room left to turn the wrench and unscrew the sensor from the end of the exhaust manifold. So, the trip to the auto parts shop to find a slotted socket. Bottom line was that I got the job done and added two new tools to my kit.