so, i bought this 1999 Mazda Miata.
the check engine light came on the day i bought the car. the dealer promised that the car would (apparently it did when he smogged it. he might have false passed it) pass the smog. however, i ran a code check and it says the cat is below threshold. and either i need a O2 sensor or a new cat. can i return the car since it doesn't pass smog like he said it would?
If you got a good deal on the car I would keep it because the both the O2 sensors and the catalytic converter are easy to replace. You can pick up a new O2 sensor for about $50 and you can reach in from either underneath, or in the driver's side wheel well.
If it is the catalytic converter, it's an easier replacement. Because miatas are all direct-fit, you don't need to worry about welding and they just bolt right on. Official Mazda catalytic converters are about $400, but you can get higher quality aftermarket converters for less than $100. When I replace catalytic converters on miatas it takes me less than 30 minutes.
Either way, it's not a big deal but I would definitely replace the O2 sensor before the catalytic converter first. I recommend doing your own work on this one because of the ease of work. Good luck and hope this helps.
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