Engine light and oxygen

I own a 2000 Toyota Camry that was given to me by my father. The check engine light illuminated last year so I brought the car in to my mechanic. He said it was the o2 sensor and changed it. That lasted about a month , and the light went on again. This time it had to do with some valves that get stuck open (or closed) but also had to do with the amount of oxygen that goes into the carburetor . I asked my Dad if he had this problem, and he told me that the engine light was illuminated often,that he had brought the car in about 6 times, but nothing was found. Previously I owned a 1998 Camry, and had the same problem; the check engine light illuminates, the diagnosis is the oxygen sensor, that gets changed, the light goes on again, this valve thing gets changed but the light goes on again in a month. I live in MA, so I can’t get the car inspected with the engine light illuminated, and it costs me about $450 a year to get the car inspected. The light always goes back on but nothing else is found wrong with the vehicle. Any ideas? I really know nothing about cars. please help

When this happens, you need to post the actual code. It is in the format of P0xxx with xxx being numbers, i.e P0420. Without this code, we really can’t help. Most Autozones will read this code for you and give you a cash register tape with the code at the top and their suggestions as to what might fix it. Just post the code.

“also had to do with the amount of oxygen that goes into the carburetor…”

Hmmm…

I believe that Toyota stopped using carburetors quite a few years before your car was manufactured, and that your car uses fuel injection instead of a carburetor.
Perhaps you are referring to the throttle body?

In any event, in order to give us a logical place to begin, you need to post the actual code numbers, as keith suggested.

In addition to the codes, if there are any operating problems it would be goo dto know. Also, whenever you take a car to a shop, it’s a good idea to have the mechanica annotate on the shop order his exact findings and anything that he did, then keep your copy of the shop order. If he HAS written anything on your shop order and you still have it, that would be a big help also.

That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.