O2 Sensor
 

How often should this be replaced? I'm doing some general maintenance, and it just occurred to me that it has probably never been replaced. Where can I pick one up from also, or will I have to go to Mazda for it?

Advanced Auto sells a generic on from Bosch that works fine. RX7.com also sells one (which I believe is the same).

They should last for a while. My OEM one failed at about 50k miles, however when I bought the car it was burning coolant so who knows. ;)

Typical lifespan is anywhere from 80,000 to 120,000 miles. It's pretty obvious when they go bad - gas mileage suffers bigtime.

If it's one of those "while you're in there" things, I'd look into getting one from http://www.oxygensensors.com - they have a Walker plug-in for $50. I prefer getting one that already has the connector on it - it's plug and play, and you don't have to worry how good your crimped connector is with a universal.

Dale

Exactly what Dale said....the site he referenced is great.

I got the one from Advanced. It's one wire, so it shouldn't be too big of a deal, plus it was only $19.95 instead of $50.