Sometimes I think these codes can drive one crazy the way everything is tied together.
Fuel trim gets feed back from pre cat o2 sensors to make adjustments. Post cat 02 sensors let you know the cat is doing its job. Just because a sensor trips the cel, and the code given does not mean that is the part that actually is bad.
Then you buy an OBD2 scanner You really go nuts because sometimes you clear a code, and it does not come back WTF. So that leads me to believe certain conditions can effect readings say rainy day a plug to an o2 sensor gets wet voltage goes wacky etc.
Then for the price of 02 sensors one is always looking for a deal. But in the end is the deal a sub standard sensor you paid 10 bucks less for, and either is lazy or does not last. You hope not.
I would say the stealership would be the one to go with after all they are your authorized good wrench mechanic. Or if the cel stays off for get about it.
