My CEL came on and I took it to mazda and they it was a cat code. They priced a new cat at 1300 + 300 for labor. I really didnt think it was my cat since I couldnt notice and difference in power or anything. So I parked it for the winter and took it to a local shop and had them test the 02 sensors. There telling me both sensors are bad and its going to be about 310$ per sensor and the Cat may still be bad. I guess my car is running lean.

Ive searched through all the posts and it seems I can use a cheaper sensor for the rear one but is anyone able to give me a good answer on exactly what sensors to order and roughly what I expect to pay. I guess I have to get the sensors done 1st and then go from there.

 

what year is your car? Cat could possibly still be under federal warranty.
O2 sensors can be bought at AutoZone, I'm pretty sure they have OEM. If not, check with Paul at Mazmart, I believe he can get them for a good price.

have you inspected the cat?
have them unbolt it and take a peak inside to see if the material is broken.

 

its a 2004, comes with a great story.

The car lost a lot of power driving last year after it warmed up a bit. I took it to the dealership and they looked at it for a day and said after 200$ in diagnostics they couldnt find anything wrong with it. I had the option of picking it up or letting them continue the diags, for there 95$ an hour rate or whatever it was. So i choose to pick up the car.

I got less than 3 miles off the lot and the car was doing it again. It felt like I had lost a rotor, if the car got below 1k RPMs it would just die, if I kept it revved up it would go just with about 1/2 power. Anyway the car was smoking and I pulled over and had it towed back to the dealership. The tow driver said it was probably the Cat jammed up and make sure they look at it. After a good reeming at the dealership this time they found the ignition coils to be bad but everything else was fine. My car had just eclipsed 79k miles.

After the coil change my car ran "fine" but was having some starting issues. It used to turn over after 1/2 a crank and fire right up, now it was taking 6-7 cranks everytime to start but once started everything else appeared normal. About 3 weeks later though the CEL came on again. When I took it back to the dealership the said it was throwing a CAT code and a needed a new converter for 1600. My milage was now just over 80k. They said the federal warranty was 8yr/80k and I was SOL. Since snow was getting ready to fall and I park it for the winter I gave up the fight. Now that its back out of storage im tryin to get it taken care of but wanted the sensors checked 1st.

Im tryin to find exactly what options I need for sensors, it seems the rear sensor doesnt have to be the "heated, wide band" that the front one is. Did Mazda use this on both front and back or are they 2 different sensors with different part #'s. The place im going to now is just giving me prices to replace whats there, but If I can find OEMs and a cheaper one that works well for the rear im going to go that route.

I will have them take a peak at the cat though, never thought of that. Thank for the help.

 

Is there a big difference in the sensors at autozone. The rear sensors range from 67$- 181$. Theres only 1 front sensor and they want 360$ for that.

And what the hell is up with the only Cat autozone sells for the RX-8. Its listed at like 56$, is that converter really gonna work in my car when the cheapest Mazda one Ive found online is 1067$.

 

The two O2 sensors are different. The front sensor does all the work while the rear handles checks and balances. As for your cat...personally...I would work with some locals to borrow a cat or midpipe to see if the problem goes away. Then I would hit up the aftermarket for a cat or midpipe depending on the laws in your area. For $56 you are probably just getting a cat resonator that you have to weld into your existing pipe, not a replacement pipe. Check places like the RX7Store for a replacement cat or hit up a local muffler shop to see what they would charge to make you one.

 

Did more research and talked with the shop, they were able to go as low as 244$ for the sensors so I had them order 1 for the front. I went to Onlinemazdaparts.com and ordered a rear sensor for 130$ so hopefully this will take care of the sensors.

They also quoted me 600$ for a new cat so already way ahead of the dealership.

 

Just buy a used cat and call it a day. It's also very rare for the front O2 sensor to go out, usually its the rear that goes out when the cat goes.