The engines in cars today use a computer to diagnose information from sensors placed throughout the vehicle to control the air, fuel and spark to make the engine run properly. One of these sensors is an oxygen sensor, which on a Lexus GS300 is placed along the exhaust. If one of the oxygen sensors is reading incorrectly, then the computer won't know how much fuel or spark to give the engine, and the result will be choppy idle and loss of power.
Raise the vehicle up in the air using the jack and secure it on jack stands. Double-check that the vehicle is secure prior to crawling underneath it.
Locate the oxygen sensors underneath the vehicle. They are small nipples that extend perpendicularly to the exhaust tubing and have a wire lead at the base. Manually unplug the harness leading out of one of the sensors.
Place the oxygen sensor socket onto the end of a 3/8-inch ratchet and place it over the oxygen sensor. There is a slot on the oxygen sensor socket that will allow the wire lead from the oxygen sensor to run out the side and not get damaged. Remove the oxygen sensor and discard it.
Place the replacement oxygen sensor in the bung on the exhaust and tighten it in place using the oxygen sensor socket and the ratchet. Reconnect the wiring harness to the pigtail on the sensor. Repeat the process for any additional sensors on the exhaust.
