Should I have to replace the o2 sensor in a 2000 Diamante with 81,000 miles? I got the car last week from a dealer and today the CE light came on. I think it was reset before we got it because after 1 week of driving it came on. The dealer claims the warranty I have covers powertrain but not the sensor. They want $500 to replace it. I think it's a rip. Anyone know where to get them reasonably priced? I've checked Advance Auto for $150+/-. I'm trying to make the dealer replace it since I still have a dealer tag. The car is brand new to us. Its Bank 2 side 1. Anyone know which one that is?

So no one is even gonna bother answering?