I've read and searched through the forums, but I want just want to verify what I think I've determined about my 2005 RX8.

Over the past month or so it has been starting harder than usual, 3 to 4 cranks instead of an instant start like normal. Took it to the dealer for an oil change, the clutch pedal TSB, and an inspection to see what the cause of the slow start was.

I was told my battery voltage was low, and that I would need new spark plugs. I said ok, and I replaced both of those myself within a week. Car still started slow, but seemed to be running normal otherwise.

Tonight as I was leaving work I pulled out of the parking lot and accelerated in first gear, and the car jerked violently. I pulled onto the road and again accelerated. This time the rpms crept very slowly to the point where the car struggled to maintain speed. I live about a mile away from work so I babied it from that point on. As I pulled down my street the CEL started to flash (assuming misfire) and I coasted home.

I left the car running, got out and looked at the Catalytic converter immediately. Noticed that it was glowing bright red around the O2 sensor bung. Went to the tail pipes and it was producing a sputtering exhaust note. Like very fast puffs of air rather than a constant stream. The exhaust was louder than normal, and again revving was near impossible.

The car has 30,000 miles on it, and these are all the symptoms I have noticed.

Is this a clogged cat? Would it be in my best interest to have it towed to the dealership? Or does this sound like an engine issue? Coils have not been changed, but was on my short list of items to do. Obviously will hold off until I determine the cause.

Thoughts?

 

If the cat was glowing then it should be the cat, you just have to convince the dealership of that. In other threads the dealers had people replace plugs and coils and stuff like that before they would even say it was the cat. Seems like some dealers are pretty stubborn, hopefully you have a good one near you that will listen.

How much is a tow going to cost you? You might try calling the dealer and seeing if you can just bring your failed cat in for inspection and get a new one that way if you have another car you can drive for now. Some people have done it this way but you generally need a good relationship with your dealer for that.

 

Well I didn't get it towed...yet. I called the dealer and was about to make the commitment, but I wanted to try a few things first as they didn't have any openings until Wednesday.

I disconnected the catalytic converter from the exhaust manifold, started it (insanely loud by the way) and revved it to see if the power was back. It wasn't, so I can rule out the cat. I still ordered the Agency power midpipe anyways, figured one less thing to break this way as I've had a bad experience with cat failure in the past.

I'm lead to believe after searching through the vast archives of RX8club that this is a coil issue. There is no sulfur/egg smell from the exhaust, but that of unburned fuel, and a lot of it. So I assume that implies combustion is not completely occurring in one or both of the rotors (my misfire CEL would confirm this). Lack of spark being the culprit due to the excess fuel, and seeing that I just replaced the spark plugs and battery those two can be ruled out as well.

Coils and wires seem to be the most recommended replacement based on what I've read, would anyone have any other ideas as to where the problem could lie? Could this be an internal engine issue? Compression loss/bad seals? Again only 30k miles, and I have no history before 22k, so I assume the ignition system was never maintenanced in with so few miles.

 

To no ones surprise but my own I'm sure, it was the coils. Glad to have my car back and glad I was able to avoid the dealer. Just wanted to resolve this thread for reference.

 

Glad to see your car is fixed and running good. Yea it still sounds like your cat is bad though. I saw you ordered a mid pipe but just a suggestion is get a new cat from the dealer. It should be covered under warranty so it should be free. That way when you put your mid pipe on you have a back up cat. I know in Indiana when you get pulled over for no cat you get a ticket and they make an appointment that you have to show up to show them you fixed it. So if that happened you could just throw the cat on for the appointment then change it back. Or you could sell the brand new cat if you choose. They are really expensive over a thousand but I'm not sure the exact number. So you could make some good money off of it. Just my 2 cents