KingAziz

I have a 2004 GT with 89k miles MT, no mods except for catback exhaust.

So I drove my rx8 to work yesterday morning and the car drove like it normally does. I started driving home after work (around 6pm) and initially it seemed fine, but when I got on the highway, the car began sputtering intermittenly and would not accelerate properly. I pulled over to the side of the highway and the car stalled. It will start back up but idles rough and idle jumps around for first minute or so then stabilizes.

The car hesitates badly upon acceleration from complete stop and will not rev past 6k. I dont know if it has thrown a code since my cel was already on from a o2 sensor that needs replacing. I've searched the forum and narrowed it down to two possible issues, either the cat is clogged or one or more of the coils have failed. I have had the coils fail on me before, but this doesn't feel the same. The engine sounds fine once the idle stabilizes and after initial hesitation, it seems to gain revs like it normally would (in neutral).

also, my car normally pops when it is revved before reaching normal operating temp then stops. I always thought this was due to my exhaust, but now the car pops everytime I let off the throttle.

I don't know much about these cars so any help would be greatly appreciated.

RIWWP

iTrader: (2)

This could also be caused by that O2 sensor that needs replacing. And the problems caused by that may have also now caused your cat failure.

If your plugs, wires, and coils are older than 30,000 miles, change them all. Waiting for them to fail first is just asking for far more trouble and expensive repairs, i.e., cat failure, O2 sensor failure, engine damage, and eventually car fires.

sonicsdaman

iTrader: (3)

Drop the cat and check it before driving it anymore it sounds like the cat is dead, and is the CEL flashing? Flashing CEL means misfire and that can be caused by coils/sparks. When where the coils/sparks changed last? I would check the cat and then replace the coils/sparks. oh and while you have the cat out fix the O2 sensor .

KingAziz

the coils and plugs are right up around 30k, I cant remember exactly when I changed them last, but they are due for replacement anyways.

What am I looking for when I drop the cat?

RIWWP

iTrader: (2)

Clean and unbroken honeycomb that doesn't look dull and clogged. You might not be able to tell that it's clogged, but if you see any cracks, chunks, broken pieces, obvious restriction, or if you can see the tip of the O2 sensor, then it has failed.

Do a google image search: site:rx8club.com catalytic converter

You will see a mess of pictures that people have taken of the internals, most of which are busted, so it can give you a general idea.

KingAziz

Thanks RIWWP. I am dropping my cat this evening to inspect and I'll update tomorrow.

btw, since the county i live in does not require emission tests, i might just go with a resonated midpipe. what do you think of AP dual resonated?

RIWWP

iTrader: (2)

Um, I recommend doing your research. I'm known to be pretty heavily biased toward the BHR midpipe. Even if my reasons are all entirely logical, some people take exception to how I wouldn't consider any other options out there, and some people see a conflict of interest with me pushing that pipe while on the staff here.

My opinion and reasons are stated in the Newbie's Guide to Modding thread, midpipe section.