You have 4 O2 sensors on your vehicle. One on each side of the cylinders before the catalytic converters, and one on each exhaust pipe after the catalytic converters.
Also, it is very unusual for all of those sensors to go bad at the same time. This hints at the possibility that your computer is faulty, or the wiring harness to the computer has some bad/corroded connections.
Your powertrain control module is located under the hood, right next to the brake master cylinder. I don't suggest that you mess with that thing yourself. (Unless you are an A.S.E. Certified mechanic)
If AutoZone can't tell you more about the possibility of you computer being faulty, go to a competent mechanic. Their computers are much more sophisticated, and they'll usually do a free estimate.
Whatever you do, DO NOT go to a dealership. They will charge you an arm and a leg, for sure.
Thursday, December 31st, 2009 AT 11:10 PM