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Does anyone else have a rough idle?

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Old 08-20-2004, 08:33 AM
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Does anyone else have a rough idle?

And im not talking about the needle on the tach. My needle drops to 1.5K when i push in the clutch, then slowly drops down to just under 1K and never moves.

I am talking about how the car feels. how the steering wheel feels, how the shifter feels. I can feel spurts of the engine through the steering wheel at a red light. I dont know much about rotary engines yet, so is this normal?
Old 08-20-2004, 08:43 AM
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For the most part it is normal. My car has its days though. Sometimes it will run rough as hell, other days it is as smooth as a babies bottom.
Old 08-20-2004, 09:24 AM
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Originally Posted by RotorMotor04
For the most part it is normal. My car has its days though. Sometimes it will run rough as hell, other days it is as smooth as a babies bottom.
ditto
Old 08-20-2004, 09:25 AM
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No
Old 08-20-2004, 09:26 AM
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normal....
Old 08-20-2004, 09:26 AM
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of course I don't speak for everyone. for me the answer is "No"
Old 08-20-2004, 09:28 AM
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I have the same little hiccup during idle. I hope it is normal. What gas are you useing. I nocticed this both with 91 and 89 octane
Old 08-20-2004, 09:38 AM
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My 8 idles rough. You can feel it in the seat, stering and pedals. It's almost cyclic in nature. A couple of seconds smooth, a couple of seconds rough, repeat. 1.6K miles on the car.

A few questions for those who can't feel the idle roughness: Have your spark plugs been replaced since break-in? Did it idle rough during break-in and then smooth out with more miles on the car?

Last edited by Dark8; 08-20-2004 at 09:41 AM.
Old 08-20-2004, 09:49 AM
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boat...The RX-8 is not made for water. Be careful.
Old 08-20-2004, 09:52 AM
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cool sounds like im not the only one then. And it is like a cycle. It will be smooth for a sec, then rough , then smooth etc. Like i said the tach needle is rock steady, so im not to worried. Just wondered if it was "normal"...
Old 08-20-2004, 09:55 AM
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I get it at stop lights a lot, which, oddly, is the only time I notice it. But, I've got 20k miles on the car and it's never stalled, so I'm not going to worry much since it's been doing it the entire time.
Old 08-20-2004, 12:40 PM
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Originally Posted by Elara
I get it at stop lights a lot, which, oddly, is the only time I notice it. But, I've got 20k miles on the car and it's never stalled, so I'm not going to worry much since it's been doing it the entire time.

That has been my experience until this morning. I was at the stop light immediately before the highway entrance, and the rpms dropped way low, my guess is between 3-5 hundred, then it returned to normal. This happened twice. The rest of the commute was OK. It actually felt like the engine had died and quickly recovered. I have 23.7 k miles.
Old 08-20-2004, 12:48 PM
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to the original poster look at the bottom of this page and you will see a list of other thread that talk about rough idle. you don't even need to use the search personally i think alot of it has to do with the engine and tranny being so close and people just arent used to the high amount of feedback that this car provides. the ppf probably transmits most of what you are experiencing.
Old 08-23-2004, 06:46 AM
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Most cars tuned for a high rev power peak will have a slightly rough idle... if it's light enough to rev that well it doesn't have quite the inertia to stay smooth at 900 revs. (That's ten times slower than the redline remember...)

You ever sat in a TVR? :D

Also as the previous poster says, the 8 is a "proper" sports car designed to give you feedback about what the engine / chassis / wheels are doing - which also means any slight roughness gets through to the driver. Sure, an Audi idles smooth as glass - which is exactly why they're REALLY difficult to drive hard.
Old 08-23-2004, 05:02 PM
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Before I bought my 8 I read a lot of reviews. The most consistent ding among all the reviews was the idle shudder. At first I thought they were being purists. After having my 8 for a month, I know what they mean and think "shudder" is an accurate description.

I would say it is normal...doesn't get better or worse. And taking a holistic view opf the car, the shdder is well within the range of acceptable, to me.
Old 08-23-2004, 05:26 PM
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Originally Posted by zevans
Also as the previous poster says, the 8 is a "proper" sports car designed to give you feedback about what the engine / chassis / wheels are doing - which also means any slight roughness gets through to the driver. Sure, an Audi idles smooth as glass - which is exactly why they're REALLY difficult to drive hard.
I can speak from experience about the Audi as well. We just traded in my wife's A4 1.8t quattro sport. Its' idle was real smooth but getting that car to move was also real hard to do. It would drive long distances using little gas but the get up and go didn't.
Old 08-23-2004, 08:11 PM
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Originally Posted by reddragonmd
And im not talking about the needle on the tach. My needle drops to 1.5K when i push in the clutch, then slowly drops down to just under 1K and never moves.

I am talking about how the car feels. how the steering wheel feels, how the shifter feels. I can feel spurts of the engine through the steering wheel at a red light. I dont know much about rotary engines yet, so is this normal?
Man befor I got the M-FLASH you could not even hear my car, but just the rotar's you know. After that I hear all kinds of things:o still love my 8.
Old 08-23-2004, 08:33 PM
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being the nature of the rotory, granted the Renesis is improved over the original b13, there is a large compression area and it needs two spark plugs per rotor. Mazda recomends 91 octane minimum. if you run subgrade fuel not all of it will burn because of the shape of the compression chamber. this unburned fuel will cause misfires and fouled plugs. try running 93 octane and see if that helps smooth it out. if not inspect the tips of the plugs. they should look lightly carboned. if they are white or very dirty then they need to be replaced. also check your oil level. these engines use oil by design so they do need to be refilled now and again. read the manual for more maintenance requirements. also don't work the engine until it warms up and especially don't shut it off cold! these engines expand and cool differently then piston engines. you can really shorten the life of it if you don't maintain it the way mazda recomends
Old 08-23-2004, 08:58 PM
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Originally Posted by bigblockbeater
being the nature of the rotory, granted the Renesis is improved over the original b13, there is a large compression area and it needs two spark plugs per rotor. Mazda recomends 91 octane minimum. if you run subgrade fuel not all of it will burn because of the shape of the compression chamber. this unburned fuel will cause misfires and fouled plugs. .......
Recommend and require are two different things. I've been running Shell 87 octane for all of my 11k miles with no problems like misfires or fouled plugs.

If you read you're manual, you'll note it says "You may use a regular unleaded fuel with Octane Rating from 87 to 90 (91 to 95 RON) but this will slightly reduce performance."

rx8cited
Old 08-24-2004, 04:18 PM
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I've read all the threads on rough idle and I'm of two minds about this.

First, the car idles rough, end of story. At around 800-900rpm, it's a bit rough in a cyclical way. I expected that and can live with it.

But second, is this issue of dipping way down below 800 rpm, to about 400 and stalling or nearly stalling. Mine did this today at a red light. One of the warning lights even came on in the car, but it blipped off as soon as the engine got it's feet back, so i don't even know, but assume it was the CEL.

In my view, these seem like different issues. The first is fine, the second does NOT seem normal or good in any way.
Old 08-24-2004, 10:57 PM
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Originally Posted by Dark8
My 8 idles rough. You can feel it in the seat, stering and pedals. It's almost cyclic in nature. A couple of seconds smooth, a couple of seconds rough, repeat. 1.6K miles on the car.

A few questions for those who can't feel the idle roughness: Have your spark plugs been replaced since break-in? Did it idle rough during break-in and then smooth out with more miles on the car?
Same symptoms here.
No, yes, and no.

It looks to me like the exhaust system as shaking the whole car. The undercarriage feels rock-steady, but the entire exhaust system is vibrating like crazy.
Old 08-25-2004, 01:27 AM
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Originally Posted by DOMINION
Man befor I got the M-FLASH you could not even hear my car, but just the rotar's you know. After that I hear all kinds of things:o still love my 8.
Same with me. Darn dealer tech snuck in the m-flash with my 21000mile service. Up until then the motor would idle smoothly at 900rpm, now it rumbles around at 700.
Old 08-26-2004, 12:53 PM
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Today my car unexplainedly jumped from 900 rpms to 1500 while I was sitting at a stop light after it was warmed up and I had been on the road for about 10 min. Not sure what was going on there. I guess I will watch it closer now.
Old 08-26-2004, 01:49 PM
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normal for me
Old 09-27-2004, 08:26 PM
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I was playing with my new CanScan today, monitoring the A/F ratio from the wideband O2 sensor. At idle my 8 shows about 14.9 and creeps to just over 15.0 then shudders and returns to around 14.9. Very cyclical as described by others. This seems a little lean and may be why we get the little shudder. Is it possible the ECU leans the motor to the point of misfire and then corrects?
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