O2 Sensor

I had my engine light come on the other day, and i thought it was probably just because of the gas cap not being tight, but i took it to autozone to get tested anyways, just incase it was something else. i guy said that it was my O2 sensor and that it was causing it to send too high of voltage. i asked him why this would be happening, but the kid was an idiot and didnt really know what it even was i dont think. i was just wondering if anyone knows why this might happen and how hard it is to change the o2 sensor. another thing is that the engine light will come on for a while then go off again. i need to get my car inspected and i cant really afford to pay 100 bucks for a new one. any advise or comments would be great. thanks.

ive never replaced my o2 censor as of yet but if u cant afford have u thought about just grabbin a wrecker one? my brother says they rip u off and has lived by the auto wrecker philosophy "If it fits in ur pocket, it's free" just a thought anyway

replacing an O2 sensor is like changing a spark plug. You unplug the connector and unscrew it. IF your car is newer than 95, you'll need to have Zone erase the code after you done changing it. IF your car is 94-older, you can disconnect the battery while you change the sensor, and that will clear the code for you. Whatever you do, don't buy a Bosch brand sensor, they are absolute junk, buy a delco so you don't have to do it again in a month. To answer your question about the high voltage, I'll ty to explain. The o2 sensor creates voltage due to a chemical reaction with the exhaust gases. The amount of free oxygen in the exhaust varies depending on fuel/air mixture, and the o2 sensor tells the computer whether more or less fuel is needed by this voltage it creates. A bad o2 sensor will cause a drop in mileage, as well as an increase in emissions that will cause you to fail a cert test.

So there is really no way that this would be associated with my gas cap being loose or anything, because i opened my gas cap and the little valvle thing that you put the gas nozzle through is open a little, it must have gotten bent somehow. is there any way that could be the reason why my engine light is on and they may have misread it somehow. becuase the light keeps going on and off.

So there is really no way that this would be associated with my gas cap being loose or anything, because i opened my gas cap and the little valvle thing that you put the gas nozzle through is open a little, it must have gotten bent somehow. is there any way that could be the reason why my engine light is on and they may have misread it somehow. becuase the light keeps going on and off.
That has nothing to do with it, just a bad sensor thats it!