Hey All!

Had a CEL about 6 months ago. Had it checked, and a bad cat/o2 sensor code (don't have the nubmer) came up. The recommedation was to do a reflash and reset.

Things were great for a while, then the CEL returned in a couple weeks ago. Same code as the last time. They checked the O2 sensor at the cat, and it was working but the reading was abnormal. They called mazda q&a and were told the cat needed changing.

My car is a 2004 and has 8000 miles on it.

My questions:
1. How could my cat have gone bad so soon? Is this unusual?
2. Would gas make a difference in the o2 sensor readings? A place I goto for premium gas has a sign on the pump that I just noticed that said that particular gas is nonoxygenated. Not sure what that means or if it has any bearing on this.

Thoughts?

 

I had the same issue. Cat was throwing codes all the time. What it probably is is that someone flooded the engine prior to your ownership (dealer) and some of that gas made its way into the cat and managed to mess things up. You may have to do a complete cat replacement depending on the damage to the cat.

 

yep^

 

I got my CEL around the same time.

Didnt even bother to pull my car to the dealer. Since I know what the code means, and I might go change my Exhaust anyway. so it doesnt really matter.

 

Me too. Threw a cel and had the cat replaced at about that mileage.

I have yet to hear a reasonable explanation.

 

I didn't get a CEL, but took my car in for rattling from underneath the car.
Said my cat broke?
Hey, who cares they will replace it under warranty and it doesn't even take that long. Go get it replaced.

 

Fair enough. Now just have to wait for the parts to come in.

 

bad o2s would definitely give you bad gas mileagle. your car would stay in open loop thus causing your car to always run more rich.