Hi all,

I have a 2011 RX-8 sport which is truly running like a dream. The only thing that has been making me worry a little bit lately is that it idles a bit rough. Just a little sputtering I suppose. I have been reading other "rough idle" posts on these forums and just about everyone is also experiencing major problems related to this. One person also reported power loss. I saw one post which said idle is rough only when the AC is running.

For me this isn't the case. The idle is only rough when the engine heats up (during the accelerated warm-up cycle, the idle is perfectly smooth). Also, the car runs like a dream other than this. It pulls very hard for a car with ~160 torque 232 bhp.

I purchased it about 1 month ago at 4000 miles. I have driven it up to 5600 now. I only use premium gas (93 oct) and I check the oil twice a week. It has consumed probably around 1 quart of oil, maybe a little more. I basically add a little oil (5w20) every two fill-ups. If this is irrelevant information I apologize.

What I am thinking is that I should replace spark plugs and maybe coils/wires. Some of the other posts on this forum that I have read recommended this, but my problem is not the same as others. If anyone has any information about this I would love to hear suggestions.

Thanks ,

Glitch

 

Just give everything a good once over. Clean the MAF, insure the plug cables are tight on the coils and plugs, check all vacuum connections, check intake tract, make sure you are not missing one of the two little vacuum caps that go on the nipples on the lower intake manifold.

 

Plug cables were the culprit on my rough idle, make sure they are fully seated and the spark plug boot clicks into place. Also before you buy spark plugs, you can remove them and take a pic for us to look. This way you dont spend money if you don't have to

 

Perhaps try the 20 brake stomp to reset the ECU and then test for a tank or two? If the problem persisted, I'd probably take it to the dealer. It's still under the bumper-to-bumper warranty, eh?

At 5600 miles, I have a hard time imagining coils or spark plugs being an issue. That's doubly so since it runs well everywhere other than idle.

Also, what does the sputtering look like on the tach? Ie, how far is the RPM dropping when it sputters?

 

Series II does not use the Series I 20 Brake Stomp for ECU reset.

 

OP does your car have a aftermarket CAI (Cold Air Intake?)...there is an M-Tip out for rough idling after a long periods of idle....see the 'M-Tips' thread.

 

Happens to my 06 too. If I drive it hard (WOT to redline for several minutes), I have 4 days of smooth warm-ups, then on the 5th day usually same problem but it's only rough on warm-up moving from 2k to 1k n back up to 2k every 2 seconds or so.

I drive very short distances to work, and in general, about 1 mile and a quarter per trip, but I try to drive it for longer distances once or twice a week.

Maybe a good fuel cleaner will help? And some hard driving

 

Hey Glitch I also have a 2011, GT. I had the exact same worry as you after I bought mine, minor sputtering that didn't even register on the tach, but you can feel it and hear it. Purchased at 32k miles, changed the plugs and coils and that sputtering went right away. However, I'm at 43k miles now and its back. I kept the old plugs and coils because they were still in relatively good shape, but I'm not terribly worried about the minor shaking (although I am certainly no mechanic).

I have a feeling a lot of people are going to confuse the "sputtering" idle you and I are expereincing with a rougher idle that a lot of the older models have experienced.

 

The odd fart, pop or splutter is nothing...and yes I know you can say it never happened when new, well guess what...our cars are no longer new once an engine is over 10,000....

A rotary is still an internal combustion motor/engine, not an electric one.

 

Wow , you are really killing your engine with love , you should not use a rotary in those circumstances...engine would never get to normal operating temps.

I have a local lady around my estate who owns a black auto 4 speed S1, she keeps it immaculate, has pink leather inserts installed in seats, and even 2 heart shaped chrome exhaust tips.
Anyway she works in my local shopping centre (don't know what shop) I see her car parked in car park every day, I know where she lives, BUT, the distance she travels day after day after day is not even half a mile one way!!

That poor RX-8 is choking a slow death...

 

I don't know if this is similar - but when my R3 is idling, it almost sounds like the exhaust is being restricted or something. I hear the constant burp, pop, pop, pop burp, pop, pop. Again, no tach fluctuation, but you can clearly hear it. When I say pop, its not like exhaust flame pops, but almost like a thud almost within the exhaust. Like there is way too much backpressure or something. Its kind of cool, actually. Although my wife asked - Is it supposed to do that? I said I don't know. I am going to try and video it and see if I can catch the sound...

 

LOL, I saw an R3 for sale on autotrader when I was looking for one in Austin, Texas. probably still on there - the guy said its not driven much and wife drove it to work 3 miles away daily or something. I read that and said to myself "Yep, this engine is screwed" and kept looking...

EDIT - Found it...

http://www.autotrader.com/cars-for-s...28898670&Log=0

 

You're probably not wrong. I do fully warm it up though, it's always 80 degrees here so it doesn't take too long. I let the car idle for a few minutes to warm up and when it warms up fully i try to do some spirited driving for the last stretch.

I'll buy an electric skateboard soon then I can only drive my 8 for longer drives once a week

 

Mine does the exact same thing! New plugs and a BHR ignition failed to remedy it so I have come to the conclusion that it is normal. It's not like this is a piston engine so I've thrown a lot of "the way it should be" stuff out the window lol

 

Mine also does this. I believe it is normal because it has been doing it since I got the car in July 2011. I am coming up on 30,000 miles soon and will be replacing my plugs. I guess we will see if that changes anything.

 

OP, are you premixing? 6 oz. of two cycle oil per tank smoothes out the idle on my R3.

 

Interesting - I thought pre-mix was not need for S2 due to improved OMP's? There was a big ole thread about this somewhere and based on my readings, I decided not to. I wonder if I need to now???

 

If you check the S2 oil and premix thread many people are premixing with their S2's. I am under the impression that all rotaries benefit from the additional lubrication.

 

hey, i am from germany and drive a 2008 mazda rx8 r3
just wanted to know, how the brake stomp method is performed for the facelift models?
cause there is no fake oilpressure which shows me if it worked or not

regards

 

There is unfortunately no visual indicator that the reset worked unless you had an obd2 monitor that shows you the fuel trims have been reset.

 

Even if it only has 10k miles, it's 2-3 years old. Those are some old plugs, that we're not driven very hard from the sound of it. I'd get new plugs and take it for a spirited road trip.

 

hey man, before i post and sound dumb and repetitive and annoying....can i dm you try to send you a video? Reading ur post makes me think that i am having the same weird idle as you were and i wanna make sure.

 

Hi, I'm from Indonesia and I drove the same car as u, an RX8 GT 2011. I have the same issue of ROUGH IDLE, but I notice that this is happening just after I change oil and the mechanic also clean up my air intake pipe and filter and also he blow my MAF sensor with an air compressor gun. Right at the next morning when I drive it I notice that my car RPM is dropping a bit and I expreiencing a power loss, but car is running ok at high speed.

 

You need to stop going to that shop or at least have a conversation with the mechanic. I have never heard of anyone using a air compressor on a MAF sensor. Compressed air won't do anything against any oil stuck on it. Are they too cheap to buy dedicated MAF cleaner?

New engine oil cannot cause any issue, although I'd double check the level given their incompetence just to be sure.

So start looking at the intake, make sure everything is put on right, the VFAD line is connected properly, and buy a can of dedicated MAF cleaner and do the job right.

 

Everything is great now, the problem solution of my rough idle is simple, I just plugged out the MAF and blow it with my mouth and put it back until clicked. DONE. Problem solved, car running smoothly without issue now