2004 RX-8 manual transmission 50,000miles


Hello,

About a month ago, I was driving on the road and it suddenly happened.

1. car really shakes

2. CEL flashing

3. huge power loss

4. It idles like it's going to die


I immidietely stopped the car on the side and towed to the dealership.


The dealership said that those symptoms happen when ignition coil fails.

So as they adviced, I did


1. replacing spark plugs

2. replacing ignition coils

3. throttle body cleaning

4. checking o2 sensor (it was fine)

5. engine oil change


After those works done, I went to drive on the road and I immediately

found that my car has less power than before. I say about 20% loss.


Acceleration is noticeably slower than before, and on the day I replaced

everything, it could not even climb a little hill on the highway (at this section,

I used to climb up with 6th gear with enough power, but car could not

acclerate even in 5th gear, so I shifted down to 3rd and climbed - but after

a few days, I could climb up with 6th gear, but with still much slower)


And a week ago, I had 1 hour driving on the highway and I parked the

car at destination. But I found that car ildes like crazy (RPM should be

around 800-900 steadily, right? but at that time, the RPM stays around

800-900, but it often goes down to 500-600 range for a second and car

shakes like it is going to stall. The RPM goes back to 800-900 range after

it shakes. It repeated. I left the car for one day and started car in the

morning, the crazy ilding did not happen anymore but stll more vabration

than before everything happened. (but still power loss till now)


I do not know what the reason is for the power loss and unstable idling.

What could be the reason??

 

How did you test the front O2 sensor?
Sure you got the order of the coils right?
What are your plugs lookin like now?
After cleaning the Throttle Body did you find that it was dirty?
Did you clean the MAF w/ the Throttle Body?

 

1) Check coil/plug order as Devilboi mentioned.
2) Make sure the plug wires are secured/clipped on the plugs
3) It would have been nice to know what the CEL code was.
4) Poor ignition (incomplete combustion) can cause issues with the catalytic converter

 

Thank you for the reply.


1. How did you test the front O2 sensor?

Since dealership did it and said okay, I did not doubt much about the result.

2. Sure you got the order of the coils right?

Since dealership did it and said okay, I did not doubt much about the result.

3. What are your plugs lookin like now?

hmm I do not know the order even if I see them..

4. After cleaning the Throttle Body did you find that it was dirty?

I did not check it. I just believed the dealership?

5. Did you clean the MAF w/ the Throttle Body?

Not yet sir.

 

Sorry to say this, but if you left the dealer and noticed it ran worse, you should have turned around and went back.

 

Yea...I had read it that you had done the work...sorry about that. Im with Jon...take it back and make them work on it some more.

 

I would take it back and tell them this and see what they say......There is no reason that talking to them should cost you money

If they suggest anything else....better think about it before they start replacing parts....maybe ask us on here again

An often found cause for the crappy idle is the engine mount on the passenger side....and the CAT being plugged or failing.......The mount won't cause power loss though

 

I actually modified my original post because I wasn't sure either and thought he might have been the one who did it too.
But then he made it pretty clear later

 

I went back to the dealership for checking again, but they said they couldn't

find any problems.


They said the senior mechanic will come back soon from vacation, so I would

go back soon.

 

did your car get any louder? Have they checked your cat converter yet?

 

What a horrible dealer...UGH. Anywho...I would start with the MAF since it is easy. Other then that...the only thing I would recommend is that you don't drive the thing because if it is a bad kitty you could be in deep dodo.

 

I don't think my car got louder and chekced the cat converter yet.

 

Any foul odors or abnormal heat coming from the center counsel area/passenger floorboard area. I would be sure to have the dealer check the cat....

 

Bad dealer... Do some basic checks and research here.

Please check that the plugs are connected to the correct coils.
https://www.rx8club.com/showpost.php...09&postcount=2

Make sure that the dealer mech reconnected all the vacuum lines around the air box, accordion tube and intake.

 

Since you're posting my wonderful MS Paint work, I'll post another

 

I hope you don't mind but it was by far the best!
Hopefully the OP can pinpoint the problem...

 

Still could be the CAT and that is the first thing I would have checked before replacing all those parts.

Bad Cat can't go uphill is classic system.

Have to manually disconnect, pull it down and look inside.

 

LOL... I don't mind... I just chuckle at how much MS Paint has made reading the layout easier.

 

The center console is a bit hot. I say it is little more than warm.

 

compression test it, and this time stay at the garage see them work on it and try get understanding from dealers that they know bit about Rx 8.

 

Talked to dealership today and here's what they told me.


They will cover the charge of the catalytic converter, by federal law.

(they said every Canadian car less than 8 yrs will have warranty for any parts relating

emission; I didn't know if there's some law like that. Anyway, they will pay for it and it's good)


And they said that I also have to replace front and rear oxygen sensors, which is not

covered by warranty. (costing CAN $780 including labour)


I haven't got any check engine lights so I asked why I need to replace those sensors.

They said that bad oxygen sensors can damage a new catalytic converter.


Simply, they want me to replace both of oxygen sensors and catalytic converter.

And they will charge me fees for oxygen sensors.


So my question is,


1. is there any chance I do not have CEL even if oxygen sensor is damaged?

2. is there any possibilities that bad oxygen sensors will damage a new catalytic conveter?


am I being ripped off? They said if I only replace the catalytic converter and if new catalytic

converter gets damaged by the oxygen sensor, they won't cover the next one.

 

The answer to all 3 questions is yes. I would let them replace the front O2 but not the rear and see if they would still cover the cat in the event of failure.

 

A low reading from the 02 sensor will trip a CEL, I know from experience. Ask them how they're finding that the 02 sensors are bad.

I would ask to see the code they might claim theyre pulling. When my first cat fried out, my rear 02 sensor was tripping a CEL which was reading 'low signal'. Once I replaced the cat the sensor is reading fine and the code went away.

I wouldn't fix it until the Cat is replaced and you see how you're car is running, that's just me though..

 

Hey Guys,

I had something similar happen to me today as well. I wasn't more then 30 seconds away from the house when I felt the heavy vibration and the idle lowering. The CEL came on and started blinking. I pulled over right away and let it run for a little bit to see if it would recover. I had to hold the gas down a little while idling because I felt like the engine would stall if I didn't. I also didn't want to turn the engine off right away because I have had it flood in the past and I didn't want to deal with that happening again because it hadn't warmed up

During the idling time, it was mostly rough with a few moments where it would smoothen out and idle normally for about 10 seconds. After I ran it for about 3 minutes I turned around to come back home, still idling roughly. I had to stop at a couple stop signs and at one of them the engine stalled because I had to take my foot off the gas to break. It took two tries to start the car again. At the other stop sign I managed to keep the idle okay because I did more of a yield than a stop. I then turned into my garage turned the car off.

Do all you experts think this could be related to the catalytic converter too, or maybe the coils like the first guy? It was sort of ironic that this happened today because I was going to be doing a lot of maintenance to it today (oil change, air filter change, manual transmission fluid and rear differential fluid change). Another note, shifting has felt a little rough in the last couple weeks, which is why I was going to change the gear oil.

So I have finished the oil change and replaced air filter but haven't done the trans fluid yet. I haven't started the car yet and before I do again I wanted to get your guys advice, based on the history I just gave. Thanks in advance