What's up guys, I got a question concerning my 2004 Mazda RX8. I got a ecu scan today and it was saying that I needed a new catalytic converter and that it's misfiring. When I'm driving the vehicle I didn't sense any misfires or anything like that. Has anyone else have these problems and if so was it under warranty. I got 65013 miles on my 8 and it's an 04.

 

its a pretty common problem, the cat should be under warranty. Misfires can be anything from a lack of power to noticible bumpiness.

 

What do you mean by lack of power or noticible bumpiness?

 

missfires can kill a cat

 

I'm thinking it might be my sparkplugs possibly.

 

what if u gutted your cat?

 

well, a misfire is most commonly noticed when you are wanting to accelerate and you press down the pedal and it hesitates or it gets going and then stumbles.

 

I had the same problem for over a year...this is after I had my engine replaced under the Emissions recal, but anyways took it in to the dealer 4 or 5 times to have it checked out. They kept giving me new plugs and coils every time. Problem is after the last time I told them to keep it and find out why the plugs and coils kept going out after 5 or 6k miles. Well, they finally called Mazda for some answers...Mazda's fix was to replace the ECU and install new plugs, coils, and wires. I've had the car back about a week and have not noticed anymore misfiring but only time will tell. Oh and the cool thing is I've been out of warranty for almost 7k miles and they still payed for everything.

 

Yep. Misfires is most commonly the ignition coils or spark plugs. If your plugs have been replaced I would look at your ignition coils. They're about $30 per coil at the dealership. I'm on my second set and am swapping them out for the Mazsport coil kit.

Your cat. is most likely because of bad coils.

Mazda should replace your cat. under warranty. The coils will be on your tab.

 

An ECU scan that says u need a new CAT. I don't believe it.

No one here has ever reported a scanalizyer saying that before.

What gauge were you using?

 

I have no idea what gauge my friend was using. He works at the Mazda dealer up the street from me. the funny part is that I never sensed anything wrong with the so called misfiring. It drives fine to me, there's no hesitation at all.

 

You can also try MAF sensor cleaner.. Mine was getting some misfires (audible at idle, and felt during throttle transitions).. Sprayed the **** out of it with CRC MAF cleaner last night, reset the ECU.. Smooth as glass now. Of course the ECU hasn't had time to build trims yet, but the difference is already pretty significant. Best $5 I ever spent..

 

ahhh maf cleaner............ every year (at least)

 

You typically will see misfires at high RPM such as when tracking the car. You don't really feel them you just see the CEL start to flash.

They are stored by the PCM so the dealer can pull them. Also the cat. does has a sensor that let's it know when the front half of the catalytic element has burned out and it should also fire off a cel. OR you may have an exceptionally good tech who has seen this before and physically unbolted the cat and looked inside and found melted element.

 

 

Hey bro'
Check my post in this same forum, "First cell in over 4 years", same problem, correct solution. I picked it up today, 4 new coils, new set of plugs and wires.
Runs like new!

 

Hey guys, I finally got a new cat installed about 2 months ago and now my check engine light is on again. It makes a weird smell when I start it up, but I don't know whats wrong with it now, can you guys help me out at all?