Just recently my Automatic 04 8 has been idleing very rough once I come to a stop. It does not happen at every stop, and it only lasts for a few seconds, but it is bothering/worrying me. I am worried that it will only get worse.

Could anyone pinpoint (as best as possible) what is could be that is making my car have a rough idle?

The only thing I can think of is that I have yet to get my 35,000 mile service yet...could that be it?

Probably the mounts. My 04 Auto does this every now and then, and it has the original mounts.

Probably the mounts. My 04 Auto does this every now and then, and it has the original mounts.

So are the mounts just getting worn down? It just started doing it over the last few days, it has never done it before but maybe once or twice...

Can I ask, does this only happen in park and drive!!

Can I ask, does this only happen in park and drive!!

It rarely happens in park, only when I am on the brake at a stop light or something along those lines.

this recently happened with me too but i think maybe mine is coz i had the battery out for a few days and i feel/think maybe the fuel trims arent adapted yet ... but its really bad possibly motor mounts too ...

A I would agree with the mounts I'm going through this issue but mine is In idle and when I'm in park and I put it in drive and vice versa!!

my AT idles rough/shakes on R,D,M and when you change gears. probably some new mounts will fix the issue.

I've had the mounts replaced previously, so that is not my issue.

However, mine is in the shop right not for VERY rough idling (even stalls), and it bogs down something fierce at all speeds in all gears. It became undriveable yesterday.

The shop says tentatively it is possibly a vacuum line, and/or idle control, or worse.

We'll see I guess.

If yours gets worse and interferes with driving, take it in!

Engine mounts can be the main issue but you say that you have a rough idle, so does the RPM dip down when it vibrates? Try getting your coils/spark plugs changed as well. I have had my engine mounts replaced and the car drove a bit better and did not vibrate at all but the idle was still kind of rough and would cause a almost violent tremble/vibration and I got the MAF cleaned and changed the coils/sparkplugs and it went away. You can also have the dealership or mechanic shop hook your car up to a diagnostic machine (I think) and find what exactly is wrong and should cut to the chase fairly easy that way.

Engine mounts can be the main issue but you say that you have a rough idle, so does the RPM dip down when it vibrates? Try getting your coils/spark plugs changed as well. I have had my engine mounts replaced and the car drove a bit better and did not vibrate at all but the idle was still kind of rough and would cause a almost violent tremble/vibration and I got the MAF cleaned and changed the coils/sparkplugs and it went away. You can also have the dealership or mechanic shop hook your car up to a diagnostic machine (I think) and find what exactly is wrong and should cut to the chase fairly easy that way.

Yeah when I come to a stop it will dip below 750 RPM and starts to shake badly and then it will go back up to its usually idleing RPMs.

Yeah when I come to a stop it will dip below 750 RPM and starts to shake badly and then it will go back up to its usually idleing RPMs.

If your idle is dropping to 750rpm then your motor mounts are not your only problem. Please give us the history on your car. The service it's had and parts replaced. Type of driving it gets(long commutes, short trip), fuel used(reg or prem), ever flooded, mods installed. Have you ever run any engine de-carbon cleaner to improve compression? Just any thing that you can add.

look at MAF and your air filter/filter box.

My car was doing this and I looked at these two things. Cleaned out the filter and the box and lightly cleaned the MAF and the violent shaking mostly went away. I still get a small dip in RPMs while idle but no for violent vibration for a few seconds and then back to normal and repeat.

Yeah when I come to a stop it will dip below 750 RPM and starts to shake badly and then it will go back up to its usually idleing RPMs.


Oh ok, then you might also have a misfire as well.

-MAF cleaned
-New Coils/Spark plugs
-Vibration through your hands could mean motor mounts lol..... Seriously.

If your idle is dropping to 750rpm then your motor mounts are not your only problem. Please give us the history on your car. The service it's had and parts replaced. Type of driving it gets(long commutes, short trip), fuel used(reg or prem), ever flooded, mods installed. Have you ever run any engine de-carbon cleaner to improve compression? Just any thing that you can add.

I got the car USED at 32,000 miles. Since then I have had the oil changed, gas cap replaced, and I have not done any Mods to the car minus the Racing Beat exhaust on the car that was on when I got it.

As for the type of driving, it is driven daily to and from college, which is about 20 miles each way.

I always use PREMIUM gas.

I have never flooded the car (but I don't know if it was ever flooded before).

I have NEVER ran any de-carbon cleaner to improve compression.

- - - - - - - - - -

Last time I took my car into the Mazda shop they told me that at 37,500 miles it was due for new spark plugs and coils, so I am TRYING to wait until then...I only have 2,000 more miles to go.

I would add a can of Seafoam or BG44K with a quarter tank of gas and run till it's on "E". If this improves things then plugs and another can will most likely help more. It's not a big deal to put plugs, coils, spark plug wires in($250-$300) and about an hour. Get a buddy and follow the "DIY" on the forum.

I would add a can of Seafoam or BG44K with a quarter tank of gas and run till it's on "E". If this improves things then plugs and another can will most likely help more. It's not a big deal to put plugs, coils, spark plug wires in($250-$300) and about an hour. Get a buddy and follow the "DIY" on the forum.

Is this the thing that blows the white smoke out of the exhaust or am I thinking of something else?

And how does this help with a rough idle?

since its been cold mine has been idling rough just when in gear and stopped. It goes away when i accelerate and after a period of time it won't even do it when i'm stopped anymore. is this just the car not liking the cold? i have an 06 AT. 23,500 miles

since its been cold mine has been idling rough just when in gear and stopped. It goes away when i accelerate and after a period of time it won't even do it when i'm stopped anymore. is this just the car not liking the cold? i have an 06 AT. 23,500 miles

Mine is about the same, but it has always sorta had bad idleing, but now that it is getting colder it is a little worse than before.

i just got the car about 6 months back with 13,500 miles on it. it runs smooth and has since i got it. this cold weather just seems to make it shimmer and idles louder when i'm stopped. it was really cool a few days ago and it was like a violent shake when i put it into gear. after just half a block when i stopped again it was not nearly as bad but it still idled louder than when it was warm. Sometimes i wonder if i'm just paranoid because i have heard the stories of the engines going bad at just over 30,000 miles.

Well I know that RX8's do not like cold weather. Make sure you let your car warm up before you start to drive it. I haven't had VIOLENT shaking yet, just a little more noticeable than in warm weather. I will probably get it checked out for my 37,000 mile service unless it gets worse before then.

Well I know that RX8's do not like cold weather. Make sure you let your car warm up before you start to drive it. I haven't had VIOLENT shaking yet, just a little more noticeable than in warm weather. I will probably get it checked out for my 37,000 mile service unless it gets worse before then.

That helps..i was wondering how they handled the cold that makes me feel a little better. i always rev at 2500 to 3000 for a period of time and let it idle for 4-5 minutes before i leave the house each day. i know its a process and i just hope i'm going about it the right way to make sure the engine doesn't go out on me.

That helps..i was wondering how they handled the cold that makes me feel a little better. i always rev at 2500 to 3000 for a period of time and let it idle for 4-5 minutes before i leave the house each day. i know its a process and i just hope i'm going about it the right way to make sure the engine doesn't go out on me.


You should be alright as long as you take the right steps to make sure you do now mess up your engine.

You should be alright as long as you take the right steps to make sure you do now mess up your engine.

I talked to a Mazda Tech last night that i know and he said that its really nothing to worry about. Just be sure to make sure the engine is warmed up. I did notice though that it only does it at 7-800 rpm in gear. So if that is what it is for anyone else just be sure to warm it up properly.

I talked to a Mazda Tech last night that i know and he said that its really nothing to worry about. Just be sure to make sure the engine is warmed up. I did notice though that it only does it at 7-800 rpm in gear. So if that is what it is for anyone else just be sure to warm it up properly.

Mine is the same way. It will drop to around 800-700 rpm (Automatic Transmission) when I am stopped, but it is fine once I begin to move.

A new IAC module did not fix my problem (dealer said the code they pulled pointed towards the IAC), so it is still in the shop.

They did a compression test and MNAO is viewing the results. I may have a new engine in my future!

On the plus side, the Yaris I have as a rental sips gas, so I may just take a trip around Ontario this weekend ;)

A new IAC module did not fix my problem (dealer said the code they pulled pointed towards the IAC), so it is still in the shop.

They did a compression test and MNAO is viewing the results. I may have a new engine in my future!

On the plus side, the Yaris I have as a rental sips gas, so I may just take a trip around Ontario this weekend ;)

Please give us the history on your car. The service it's had and parts replaced. Type of driving it gets(long commutes, short trip), fuel used(reg or prem), ever flooded, mods installed. Have you ever run any engine de-carbon cleaner to improve compression? You might need this to clean up the carbon buildup from a lot of short drives and not much red lines. Just any thing that you can add.

The last couple of months are short trips in heavy traffic. The few months before that, medium trips, all highway.

Only mods are a K&N CAI. I flooded it once a year or so ago (the dealer changed the plugs), however the dealer that has it presently has flooded it twice in the last 2 days as it has obvious issues idling!

Other service it has covers the new battery and starter, new engine mounts, never been decarboned though.

I use middle grade gas, I believe ~90 octane.

I have extended warranty, so I am covered should a new engine be put in. The dealer its at is the largest volume RX-8 dealer in Canada, and I do trust they know what they are doing. They have treated me well during my ownership, so I really do not have any reason not to think they are vetting this properly.

Cheers

How much would new Engine Mounts cost?

How much would new Engine Mounts cost?

I think Engine Mounts are covered under Powertrain Warranty.

Mine is the same way. It will drop to around 800-700 rpm (Automatic Transmission) when I am stopped, but it is fine once I begin to move.

I had the spark plugs, plug wires, coils, and mounts all replaced last week by the dealer because of rough running "marbles in a can" and now it is doing exactly what you are describing at idle (mine's a stick shift)....so this is very interesting. :tear:

I was wondering if they set the idle too low when they did the work last week. If I rev to above 1000 at the stop lights it seems OK but sounds shitty as soon as it drops down to 800/900. After about 10 minutes the idle sustained itself at 1000 and no more issue...it was just the first ten mins of driving.

I am going to try the MAF cleaning. How easy of a job is that??? Anybody??? Are there directions on the DIY forum?

I think Engine Mounts are covered under Powertrain Warranty.

I had them done at just above 60K last week (no more warranty???).
I paid $350 at the stealership to have them replace the two mounts.

Sounds like you are in need of a new motor, I would try the seafoam and if that doesn't help at all then take it to the dealer

Has anyone here tried cleaning their throttle with carb cleaner and a Scotch-Brite pad? Electronic throttles are particularly susceptible to buildup around the edges of the butterfly valve. I had to scrub the hell out of the throttle on my 1.8t before it would idle properly.

this recently happened with me too but i think maybe mine is coz i had the battery out for a few days and i feel/think maybe the fuel trims arent adapted yet ... but its really bad possibly motor mounts too ...Most cars need to be run all the way from idle to redline at WOT and part-throttle a couple of times before the fuel trims can be calculated accurately. One more reason to redline it once a day.

Sounds like you are in need of a new motor, I would try the seafoam and if that doesn't help at all then take it to the dealer

Are you talking to me when you say that?

Does anyone have any advice on this? Mine does the same thing it hangs around 800 rpm and it vibrates like crazy when it idles in drive and reverse.

Does anyone have any advice on this? Mine does the same thing it hangs around 800 rpm and it vibrates like crazy when it idles in drive and reverse.

Need info on your car: year, mileage. Last time your plugs, coils and wires changed. Any warm-start issues?

Need info on your car: year, mileage. Last time your plugs, coils and wires changed. Any warm-start issues?

I have a 2004 automatic with 63,000 miles on it. I just got the coils, spark plugs, and wires changed about a month ago. And i dont have any warm-start issues. I also got a new starter when the coils and all that was replaced. Any ideas?

I have a 2004 automatic with 63,000 miles. I just got the could, plugs, and wires changed a month ago. And no i dont have any warm start issues, i just got the starter replaced with all that.

Clean your MAF sensor with electrical contact cleaner, and check your air filter (replace if necessary). While your at it, check for any sign of oil in the air intake.

Clean your MAF sensor with electrical contact cleaner, and check your air filter (replace if necessary). While your at it, check for any sign of oil in the air intake.

I just cleaned my MAF sensor with that cleaner and my air filter is clean i checked it when i cleaned the MAF two weekends ago. There were no sign of oil in there.

I just cleaned my MAF sensor with that cleaner and my air filter is clean i checked it when i cleaned the MAF two weekends ago. There were no sign of oil in there.

Check the motor mounts for cracks or breakage. If ok, then it could be due to carbon buildup in your engine. I would get a compression test at the dealership just to rule that out.

I also have an '04 RX8 Auto, and my car exhibited the same issues with rough idle at 800 when stopped and in drive. It was especially noticeable with the air conditioning on, and backing up in reverse. But I also had warm start problems which was a sign of low engine compression. Got a compression test ($89), and it failed on the second rotor. I ended up getting my engine replaced under warranty at 153,000 KM's (or 95,000 Miles). Ever since the engine was replaced, I've had no rough idle issues.

Check the motor mounts for cracks or breakage. If ok, then it could be due to carbon buildup in your engine. I would get a compression test at the dealership just to rule that out.

I also have an '04 RX8 Auto, and my car exhibited the same issues with rough idle at 800 when stopped and in drive. It was especially noticeable with the air conditioning on, and backing up in reverse. But I also had warm start problems which was a sign of low engine compression. Got a compression test ($89), and it failed on the second rotor. I ended up getting my engine replaced under warranty at 153,000 KM's (or 95,000 Miles). Ever since the engine was replaced, I've had no rough idle issues.

I got a compression test around october and they said that everything was fine. So idk. I also noticed that it was especially noticeable with the air conditioning on, and backing up in reverse. When i got the spark plugs and all that fixed they wanted to replace the engine quickly and then a day later were quick to change their mind. How do you check if the motor mounts are cracked?

I got a compression test around october and they said that everything was fine. So idk. I also noticed that it was especially noticeable with the air conditioning on, and backing up in reverse. When i got the spark plugs and all that fixed they wanted to replace the engine quickly and then a day later were quick to change their mind. How do you check if the motor mounts are cracked?

Why did they change their mind on the engine replacement? If it passed the compression test, then your engine is not the issue.

I would report the problem to the dealership, and get them to check the motor mounts. You can check them yourself, but you would have to pull your front wheels off and peel back the splash guard to inspect (mainly the passenger side mount is the affected) - check out this thread HERE (http://www.rx8club.com/showthread.php?t=60828). Apparently they have redesigned the mounts with a heat shield and are more resistant to breakage.

Why did they change their mind on the engine replacement? If it passed the compression test, then your engine is not the issue.

I would report the problem to the dealership, and get them to check the motor mounts. You can check them yourself, but you would have to pull your front wheels off and peel back the splash guard to inspect (mainly the passenger side mount is the affected) - check out this thread HERE (http://www.rx8club.com/showthread.php?t=60828). Apparently they have redesigned the mounts with a heat shield and are more resistant to breakage.


Okay so what do the motor mounts actually do? And how would they stop the vibration? Ive always wondered that. And im not quite sure why mazda backed off with changing the engine. We had it all set for them to change it and then the next day they called and said it was the starter instead and totally backed off with changing the engine.

Okay so what do the motor mounts actually do? And how would they stop the vibration? Ive always wondered that..

http://tinyurl.com/6jlz75x

http://www.ehow.com/about_5266976_motor-mounts.html

So does that make sence about why they backed off with the engine?

Okay so what do the motor mounts actually do? And how would they stop the vibration?

The mounts act as a shock-absorber. Without them, engine vibrations would be amplified through the frame of the car. A cracked mount will also cause excessive vibrations with the exact symptoms you are having (read the thread I pointed out in my last message). The original engine mounts in the '04-05 were prone to cracking on the passenger side due to heat from the exhaust manifold, and so they were revised.

So does that make sence about why they backed off with the engine?

Depends on what you originally brought it in for. If you had starting problems, and replacing the starter solved that, then yes it makes sense. They probably realized the engine passed a compression test, therefore it wasn't the problem.

The reason they replaced my engine was because it failed the compression test. The warm-start issue I was having was a major symptom of low compression. So it made sense to replace mine. I'm not sure what they did to my car, but I reported the engine vibration problem and told them to check the mounts, before they replace the engine. Had no problems after that.

Depends on what you originally brought it in for. If you had starting problems, and replacing the starter solved that, then yes it makes sense. They probably realized the engine passed a compression test, therefore it wasn't the problem.

The reason they replaced my engine was because it failed the compression test. The warm-start issue I was having was a major symptom of low compression. So it made sense to replace mine. I'm not sure what they did to my car, but I reported the engine vibration problem and told them to check the mounts, before they replace the engine. Had no problems after that.


I took it into the shop due to hard starting and a really rough idle. They did the zoom-zoom cleaner, it helped some. And then they replaced the starter. I have no problem starting it now. I forgot to ask them about the mounts, do you know how much that would cost for them to check that?

I forgot to ask them about the mounts, do you know how much that would cost for them to check that?

Not sure how much, but it's easy to do and should take less than 30 mins. All they have to do is remove the front wheels and peel back the splash guard to examine. I would stress to them that the rough idle (which is what you originally brought in for before), still isn't fixed. So they really shouldn't charge you for the inspection.

Okay thank you I'll get that checked out

Not sure how much, but it's easy to do and should take less than 30 mins. All they have to do is remove the front wheels and peel back the splash guard to examine. I would stress to them that the rough idle (which is what you originally brought in for before), still isn't fixed. So they really shouldn't charge you for the inspection.


Hey i noticed today that it doesnt idle as rough when it is watm out. It only idles REALLY rough when its cold. Why is this?