2000 Toyota Camry XLE V6 Engine Light

My car has 64,000 miles on it. It has received the very expensive 65,000 maintenance some time back. It is not driven a great deal. Over the weekend the engine light went on. My mechanic hooked up the computer and it told him the problem was with the fuel oxygen ratio meter, which he then replaced. They test drove the car and the light was gone. When I was driving him back to the shop, the light went back on. I checked a website with car complaints, and saw this is not uncommon. What should I do? I have already spent close to $500 on it.

engine lights coming on are not uncommon. But they can come on for hundreds of different reasons on each car. You need to have the codes read again. Don’t pay your mechanic to do this, go to the nearest Autozone parts store and they’ll do it for free.

Also, I’m not aware of a “fuel oxygen ratio meter” is this the MAF sensor under the hood between the air filter and the engine or the O2 sensor in the exhaust or something else?

The fact that a computer may spit out a certain code does not mean that a particular item is bad; only that it’s a starting point for diagnosis.

No idea what this fuel ox. ratio meter is but what you should do is drop by a local AutoZone, Advance, Checkers, etc. and have them scan the car.
Post any results back here for further discussion. (These auto parts houses will perform this service for you free and it only takes a couple of minutes.)