I sure hope nobody followed this advice for adding lube to the studs. What can require 55 ft-lb torque dry, only needs 30 ft-lb lubed. This is at least 80% over torqued condition. You can seriously over stress the threads and the studs and/or nuts will fail! The torqued values given are from the manufacturer are for dry conditions. Do not modify this for your own safety. Two degrees in Mechanical Engineering and a career in machine designing gives me the qualifications for these statements.
It is O2 sensor, bank 1 sensor 2. It is located just after the Catalytic convertor. You need to remove the 4 bolts holding the driver's seat down and tip the seat to the back to access the sensor plug, which is under the carpeting.