06 RX8, New Engine, Car turns off on idle

sdxicana

Member
I have a 2006 Mazda RX8 automatic, I'm the only owner. It currently has about 80K miles on it. Just last week I got it back from the shop, I had to have the infamous engine replaced because of the compression problem. To top it off, I also had to get a new radiator because when they took off my old one, I guess the seal or whatever, which they said tends to fall apart, broke. And I guess I couldn't just replace that one piece, I had to put a whole new radiator. In addition to that I also had new spark plugs put in. So after 2 weeks of it being in the shop I finally get it back, new engine, new radiator, new spark plugs. The car drives great, it feels very smooth. But right away, after I picked it up from Mazda, later that evening at a stop light my car just shut off. I put it in park and turned it back on with no problem. Then about 10 minutes later, I came to a stop light and was about to make a right turn, and as soon as I stopped, boom, shuts off again. Turned it back on again with no issues. I took it back to Mazda the next day, they kept it for another day, they checked "everything" according to them, and they drove it around a couple different times, and could not recreate the problem or find anything wrong. Maybe something was just reseting itself they said. Whatever, I took my car back. And sure enough, yesterday driving it around it happened again twice. Both times as soon as I came to the stop light, the car just shut off. And again once yesterday. UGH I"m so frustrated, I've started keeping a log of every time it happens and what time and date. I pretty much hate even looking at that Mazda dealership now, I feel like I fracking live there now. But I"m not going to have a choice, if this keeps happening next week I need to take it back.

But has anyone had this problem? What could it possibly be (scratch)? I don't have anything aftermarket on my car. Well besides the new radiator they just put in, that's aftermarket.
 
What you are describing could be the computer "learning". Sometimes it takes a few drive cycles for the computer to get the idle right.give it a day or two. If the problem persists or if it ever happens when you are not at idle then you have cause for concern. Idle speed can be affected by a lot of factors and rough idle and stalling are not uncommon on a new engine, or a new tune for that matter.
 
What you are describing could be the computer "learning". Sometimes it takes a few drive cycles for the computer to get the idle right.give it a day or two. If the problem persists or if it ever happens when you are not at idle then you have cause for concern. Idle speed can be affected by a lot of factors and rough idle and stalling are not uncommon on a new engine, or a new tune for that matter.
I'm going to go ahead and ask even though I suspect you'll have no idea... What's the fuel trim look like off idle? Long term and short term. I suspect a vacuum leak. Is this accompanied by any other symptoms? MIL perhaps? Does this occur with the AC on or off? If not sure, keep note. Also, when this happens does the tach immediately fall or does it happen slowly?
 
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I'm going to go ahead and ask even though I suspect you'll have no idea... What's the fuel trim look like off idle?
It looks like an elephant.....wait no a frog..... your right i have no idea.

I suspect a vacuum leak. Is this accompanied by any other symptoms? MIL perhaps? Does this occur with the AC on or off? If not sure, keep note. Also, when this happens does the tach immediately fall or does it happen slowly?
All good ideas and good questions.
 
That was for the OP, solidtrance.
 
Ah ha.

To the OP, you can log all this if you have an AP.

Merry Christmas everyone. I just watched the kids open their presents. Oh to be a kid again!
 
I'm going to go ahead and ask even though I suspect you'll have no idea... What's the fuel trim look like off idle? Long term and short term. I suspect a vacuum leak. Is this accompanied by any other symptoms? MIL perhaps? Does this occur with the AC on or off? If not sure, keep note. Also, when this happens does the tach immediately fall or does it happen slowly?

Haha, you're right I have no idea what any of that means. As for any other symptoms, not really, I've been logging it every time it happens, the only real thing I can really say seems to be common is that when I've been driving fast and come to a quick stop, it's more likely to shut off when I hit a complete stop. It's not every time it has happened, but I've noticed most times its happened it's been in this type of instance. And I can feel it now when it's about to happen, it does like a little shake and boom, off. And usually the AC is off in most instances as well. It has still continued to happen. It doesn't happen every time I drive, but it seems to have happened almost every day since, at least once during the day sometimes. I can't seem to re-create it happening on purpose, it just randomly does. I'm going to continue to log it, and right after the new year I'm going back to Mazda with my log of every time its happened so the service guy doesn't think I'm just a crazy lady lol. There's definitely something happening here, if it was just the car "re-setting" itself or learning or whatever, I would think by now it would be all good. But up until last night it happened again, so I know something's not right.
 
Since it has been more than a few days I would tend to agree with the comments Preferio made. Vacuum leak or maybe some sort of EGR problem (which can also cause vac leak). It is very unlikely that the computer is still "learning".

I would also wonder if it couldn't be somehow related to your automatic transmission. Maybe someone with more experience with the interaction between an auto trans and the ECU can provide some feedback.

I have no experience in this area and I don't know what could cause it, but this could explain your symptoms.

On that note, has this ever happened after a few seconds at idle or does it only occur immediately after stopping?

Has it ever shut off while you had neutral or reverse selected?

Is the car doing anything else that is unusual even if it appears to be unrelated? Any clues may help.


Sounds like your dealership is typically useless for our car, don't give up yet. The solution will turn out to be something really simple and hopefully inexpensive.
 
It actually has happened before after it has been idling for a few seconds. Not often, but like the very first time it happened I was at the stop light and didn't even realize it had turned off until I went to hit the gas. But I would say most times it's been immediately after I came to a complete stop. It has never shut off in any other situation, such as neutral or reverse. I haven't really had much else unusual happen since I got my car back other than this. If it is indeed the transmission they better figure it out now, because it's still under warrantly for another 19k miles lol. But yea, I dunno the dealer techs just don't seem to know that much, even though it IS a Mazda Dealership! If they still can't find anything, I'm for sure going to suggest they check out to see if it could be a vaccum leak or an EGR problem or even a transmission problem. Whatever it is, They are the ones that put the engine in, they should freaking figure it out! That's the part that frustrates me most. I'm going to go back tomorrow with my long list of incidents since I got my car back and tell the Service guy he NEEDS to get his tech to figure out the problem.
 
I've been a shop manager for 7 years now and I know people don't believe me when I tell them the same thing sometimes, but it happens. There are times when a tech or service manager are unable to duplicate the problem and everything that would cause the symptom you described tests good. It's just as frustrating for us as it is for you. Well, as long as you're a good tech. When you said, "It has happened beofre..." did you mean before the engine replacement?
 
MIL = Malfunction Indicator Lamp, more commonly referred to as a "check engine" or "service engine" light.
 
It never happened prior to the engine being replaced, like ever. It only started happening like ON the day I got my car back after the engine being replaced.

So I took my car back, they had it for like 4 days and could NOT figure out what the problem was. They were able to duplicate the problem, I told them exactly when it was happening, when the car goes fast and comes to a quick complete stop. So they were able to recreate the problem easily. But they tell me they pretty much tested everything under the sun on that car, including doing some computer updates to my transmission and could not come to a definite conclusion. They finally called the Mazda tech line and their suggestion was that it was a bad throttle body. So they said that the tech cleaned out the throttle body and that did not fix the problem. So their final diagnosis is that now the throttle body needs to be replaced. They tell me that they could say with 99% assurance that will fix the issue, but they can't guarantee it, they are basically just go by what Mazda tech line is suggesting is the problem. It would cost me ANOTHER $1000+ to get that replacement.


Quick vent....




ARRRRRRRRRRRRRRRRRRGGGGGGGGGGGGGHHHHHHHHHHHHHHH



OK I'm done now.....now I have to figure out what the flip to do about my car =/, I have ONE year left to pay the dang thing off, just one more year. But I hate the idea of paying over a grand (over the $900 I've alrady paid for the other stuff) for them to replace something that they can't guarantee me is the problem.

(fight)
 
I doubt that a new throttle body will fix it. Very unlikely....unless they broke it when they were doing the engine swap. I think at this point these guys have demonstrated pretty definitively that they do not deserve any more of your business. If you want to replace the TB you can get one from a recycling yard and do the work yourself.

Have you noticed whether this happens with any amount of gas in the tank. Perhaps the FP was damaged or the fuel filter is clogged and as the gas moves forward on a hard stop there is a momentary interruption in the flow of gas?

Do you know how to check for vacuum leaks yourself? Preferio, any suggestions here?

Kind of grasping at straws, but you are wasting your time with this dealership. Do you know any of the other San Diego RX8 folks. I met a few in the summer of 2011 when i was in SD for a school. They were a great group and I am sure they would be able to give you some suggestions of where you could take your car for more reliable help. Let me know if you need me to get you in touch.
 
I doubt that a new throttle body will fix it. Very unlikely....unless they broke it when they were doing the engine swap. I think at this point these guys have demonstrated pretty definitively that they do not deserve any more of your business. If you want to replace the TB you can get one from a recycling yard and do the work yourself.

Have you noticed whether this happens with any amount of gas in the tank. Perhaps the FP was damaged or the fuel filter is clogged and as the gas moves forward on a hard stop there is a momentary interruption in the flow of gas?

Do you know how to check for vacuum leaks yourself? Preferio, any suggestions here?

Kind of grasping at straws, but you are wasting your time with this dealership. Do you know any of the other San Diego RX8 folks. I met a few in the summer of 2011 when i was in SD for a school. They were a great group and I am sure they would be able to give you some suggestions of where you could take your car for more reliable help. Let me know if you need me to get you in touch.

Thank you. So yesterday and today I was determined to just suck it up and trade the car for something else. I've been at a couple different dealers and today I actually went back to the Mazda Dealer to see what kinda of deal I could get maybe on a Mazda 3. Wow, they were drooling over my car, they reallly wanted my car, but the most they will give me for it is $7k....well the catch there is I still OWE $7,800 on it. The more I was there, the more I looked at my car, the more I felt a pit in my stomach. The more they gushed over my car and talked about how they couldn't keep them on the lot and how they have actually been trying to get someone to trade their car in because they have so many customers that ask for RX8's......the more I want to keep my car. I know at this point it's probably a money pit, but my car is in GOOD condition! I have had my car for 6 years, I bought it brand new with 40 miles on it. Besides a couple of little blemishes on the body, I've taken good care of it. As soon as I get close to buying something else, I start feeling regret for letting my baby go, even though I haven't yet.

I'm not sure now that I'm ready to let her go. I WANT to get a second opinion now, I want to see what I can do for my car. I would LOVE it if you all could help me find some contacts in San Diego that I could go to and see if I could get some more opinions.

Am I wrong for being so attached to my car? LOL
 
You are not wrong, you just have a great car (even if it is a little under the weather at the moment). Sending you a PM.
 
Perhaps Rotary Power in Gardena may be able to offer you some assistance with troubleshooting.
 
OP, do something for me if you're still checking this forum...

Clear the vehicles VRAM- This is a memory bank that stores the information pertaining to the eccentric shaft sensor and should ALWAYS be cleared when the sensor or engine are replaced. I would hope that a Mazda tech would know that, but it seems even the dealership technicians are in the dark when it comes to RX8s.

Turn the key to the ON position, but do not START it.

Pump the brake pedal 20 (TWENTY) times withing 8 seconds.

Start vehicle and drive.

This may not help your problem, but it's something that you can do that is FREE.

Another couple of componenst that you might want to have checked would be the canister purge solenoid and the high pressure fuel pump relay. A Master Mazda tech by the name of Guy Dribble who writes technical information and repairs for a service I use has provided me with many fixes on other Mazda vehicles and there is a repair-trac that lists these two components as possible causes for this problem.
 
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So after I took my car to a rotary specialist, he found a code that popped up for the transmission. Since he doesn't do tranny work he recommended I go to like an Aamco to get a second opinion. I took my car to Aamco and they determined I need a tranny rebuild. That my problem has nothing to do with the throttle body. So that's where I am now. My car still runs, but it still has this problem, and now I have to find a way to save up enough money to get my tranny rebuilt before my car gives out on me!!
 
Do you know what DTC (diagnostic trouble code) was stored in the fault memory? If so, post and I'll do some more research for you and/or give you my professional opinion on it. Since you've taken it to someone that specializes in rotary engines, I feel more confident in his findings, though for him to just offer up business to someone else like Aamco because he "doesn't do transmission work" seems to me like he wasn't really sure of your problem and would rather someone else make the call and be stuck with the problem if that doesn't fix it.

I have primarily worked on European cars for the past 6 years and on quite a few vehicle manufacturers require the transmission to be relearned or to reset the adaptation values after the TCM has lost power- battery replacement, engine replacement, etc. This might be something to consider, but I am not sure this is required on the RX8s equipped with automatic transmissions.
 
Was this issue ever solved? I'm having this exact same problem. Just had a brand new engine installed and the stalling at idle issue started. sometimes it revs 'hunts' up and down between 700rpm~1200rpm until it finally stalls out when idling. The dealership couldn't find an issue. No fault codes on ECU. Engine shows good compression and no vacuum leaks. The Gas pump was tested and gas pressure is good. The ECU was upgraded and reloaded with new maps. All driving history was cleared, ESS was reset and VRAM cleared. The car was driven for new mapping until it completed all cycles. Voltage regulator shows good output. I have replaced the MAF, spark plugs, wires, Coils, ECU/PCM adn the air sensor in air intake. The shop is telling me they are going to have to rebuild the "Brand new" engine to see if something was overlooked at my expense with no guarantees.
 
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