Hello. Is it a bad idea to buy an 03 Avalon with a bad O2 sensor then drive it 120 miles home? I'm not sure if it's the upstream or downstream sensor. Or could I fix it on site? Let me know.
Depending on the location of the faulty oxygen sensor, it might just affect your mpg. Regardless, It is Ok to drive the car with a faulty oxygen sensor.
Thank you. I've been looking for an avalon for a while so hopefully that's all that's wrong.
You're welcome. Make sure you find a mechanic to check the car before purchase.
could I fix it on site?
Of course. You could change it out. They're usually pretty easy to get to. Just pick up one of those O2 sensors sockets.
But ... IS that the actual problem, or is it something else? How do you know?
That's all the seller has said. I will check the codes when I look at. I will definitely change it when I get home, I'm glad 120 miles isn't too bad. Are there any signs of catalytic converter failure that I need to watch for?
yup that's what the downstream O2 sensor is for ... measuring CC efficiency.
I think there's more info about investigating that in our FAQ (under P0420)