The Concorde's name was more than just a marketing gimmick -- it was a statement of purpose. The Chrysler Concorde and the supersonic Concorde airliner after which it was named had a great deal in common: revolutionary designs that cheated the wind, and looking like nothing else on Earth, these wing-shaped wonders seemed to arrow directly toward the future with their swept bodies and pointy noses. But like its airborne predecessor, the Concorde and its LH-body brethren ultimately proved a bit too futuristic, a bit more than was completely necessary for a buying public that wasn't quite ready to let go of the past.
Bring the engine up to operating temperature, shut it down and allow it to cool for five minutes or so. Oxygen sensors are far easier to remove when the pipes are warm or hot -- use caution when working around the catalytic converters, since they may be far hotter than the rest of the system. Use a floor jack to lift the front of the car, and secure it on jack stands.
Locate the oxygen sensors; you'll find the "downstream" sensor or sensors in the exhaust pipe under the car, after the converter or converters, depending on which engine you have. The upstream sensors are in the exhaust manifolds, and both of them are readily accessible from the top on this longitudinally arranged engine. Once you've located the faulty sensor, unplug its wiring harness.
Use your ratchet and O2 sensor socket to unscrew the sensor from the pipe or manifold, expecting it to put up some resistance. With the sensor out, run a thread-cleaning tap -- or chaser -- down into the hole and back out to straighten out the threads and ensure an accurate torque reading.
Thread the new sensor into the hole by hand until it bottoms out. Use the torque wrench to tighten the sensor to 20 foot pounds for the 2.7-liter, or 33 foot-pounds for the 3.2-liter engine. Plug the sensor back in, and lower the car. Start the engine, and watch for the check-engine light. If it's still on, take the car to your local chain auto parts store, and use the store's OBD-II code scanner to clear the stored trouble codes.
