Last week I stareted getting a rough idle and blinking cel at startup. After reving it a bit it would go away and the ngine would run fine throughout the day albeit with the engine light on. The light would even reset itself after a few starts.

I took it in to mazda they told me I had multiple codes and nedded a tune up and new cat. 2 grand for the cat alone as I have 98k miles. When I told them I didn't have the money for a new cat the tech proceeded to tell me the RX8 tech just bought an aftermarket exhaust system for his car and would sell me his old one (on the side, cash) for $500. I told them just to do the tune up and if the cat was still acting up I would maybe take them up on it. They called me later and said my tune up was done and that they cleaned the cat (unclogeed it) and now it was flowing a 6. Was flowing a 16 when I brought it in (normal for an RX8 is 7-9 they say).

Well they did the tune-up and the car was fine for a couple of days. Now the weird rough idle at starup is back with the blinking engine light. after about 45 seconds it revs fine. I don't feel any loss of power while driving. WHAT CAN THIS BE. I don't trust the dealer.

 

Well if you live in NJ and only have 98k on the car by law they have to replace the cat free of charge. There is a warranty for 10yrs 100k miles on the cat

 

yeah, emissions is typically covered to 100K

 

what they said.

they have to do it by law. its under warranty and its emissions. they should know better than try to mess with the EPA. come back and tell them you found out its under warranty and to speak to their manager. ask why you were told you would be charged for this. if they refuse to do the work, report them to the EPA.

also, even if the agreed to do the work, dont go back there. i always think that if you have a tiff with a dealership, they are going to be cutting your brake cable while they are servicing your car.

 

they probably did it because that guy was trying to make some $$$ by selling his cat on the side.

 

probably.

shady people.

 

Run in the opposite direction and take your car. This statement alone proves they are blowing smoke. There is no such procedure as 'clean the cat' unless they destroy the cat in the process and leave you catless (illegal to do).

Find an honest dealer, even if you have them do any work, I would be very suspisious if they did it at all, or did it correctly if they did anything. It should be under warranty but the term in months and miles does vary by state I believe. Check your documents, or state web site they should have the info.

 

80k miles is what I found out on the web. Where are you guys getting 100k?

 

hmmmm, you might be right


Let me keep looking.

 

http://www.epa.gov/otaq/regs/im/obd/warranties.htm#1

 

yeah 80k is what I found.

The thing is I spoke to a reputable rotarty tuner today and explained what's going on and he said it doesn't sound like the cat at all. I mean the car runs fine after about 20 seconds of rough idle it smooths out. Only when cold starting in the morning or when I get off work. Once I drive it and turn it off it comes right back on ok, revs no problem. I was told if it was the cat there would be drivability issues.

 

RP Supercat here you come!

 

That same rotary mechanic told me to get a stock (prefferably used) cat as that all other cat burn out too fast. Mentioned the Random Tech cat might be the best aftermarket one for the 8.

I don't want to spend money on the cat if the engine light is going to keep coming back on. If I do get an aftermaket cat, would it just bolt on to my existing exhaust?

 

the first batch of RP cats did have a couple that burned out prematurely but RP did a hell of a job working with those owners and providing replacements, etc.

the new version should hold up pretty well. I've seen people on here with 30,000+ on them with 0 problems.
RP supercat is a direct replacement so it'll bolt right into your car.

Oh, and NO CEL with the RP supercat since the 02 sensor remains in place

 

Where can I get a RP supercat?

 

http://www.rx7.com/store/rx8/rx8exhaust.html

 

could I buy the midpipe and the RP supercat and swap out come inspection time. Do they bolt on that easy?

 

they're pretty easy to bolt on, just make sure the car is completely cold or you'll hate life. (hot gasoline is not your friend)
I think the gaskets are only one-time use though, might need a new one when you swap.

 

I don't know about the clogged cat explanation. In my past experiences with failed cats on my FC GXL and Turbo II, it seemed that the hotter the bad cats got the more restricted they became. With that said, your flow should be getting worse throughout the day if your cat is suspect.

Perhaps you could try cleaning out your intake and/or throttle body. Oil and dirt might have gotten on the throttle plate hinges, causing the throttle to get stuck at points or have erratic movement - in which case the computer might try to compensate by modulating the dbw motor or dumping fuel, etc... Pretty much results in rough idle and check engine light.

You might be due for a new O2 sensor as well.

 

I got a new O2 sensor last October. Car runs fine after 20 seconds, been that way for over a week. Just had a tune up and it's back. Maybe I need another one.

I'm getting paranoid about this now. I even thought someone put something in my tank at one time. sometimes when I fill up my door pops back open.

 

could this be the water pump? I've replaced that about 3 times since I bought the car. How about the fuel pump?

 

This sounds like what was happening to me. I was getting missfire codes. When I went to start it in the morning, it would run ruff for a minute then clear up. It would run fine for the rest of the day.
Coolant was leaking into the rear rotor after it sat overnight. Engine was replaced.

 

You're scaring me. I have 98,000 miles and can't afford to buy a new or reman engine. Has there been any instances where Mazda has replaced engines with this amount of miles on them? I really took good care of her.