Why is my RX8 stalling?!
 

UPDATE: This thread is a list of problems with my RX8 that resulted in engine replacement. If you are having the same problems as me. I highly suggest you get a compression test done to see if your engine is failing.

Hey guys so today when coming home from work my rx8 stalled on me at a stop light...the car became very sluggish out of 1st gear. Taking a couple seconds to accelerate but once out of first, it drove fine. This slow acceleration continued for a few stop lights and I noticed the RPM was dropping below 750 at idle and was shaking the car...eventually I stopped at a light an the RPMs dropped to Zero and I got no acceleration whatsoever. Engine turned off and no throttle response. I turned the car off and it took 3 tries to get it to start. It cranked and cranked. I inched my way home an when I pulled into the driveway, and put it into park, the RPMs once again dropped and the car stalled.

Here is what I have done to sum it up:
-new plugs
-new coils
-new wires
-new battery
-seafoamed engine (Insane amount of smoke)
-compression test (passed)(Ended up failing second time=new engine)
-Removed AEM CAI for stock intake
-cleaned MAF sensor
-Reset computer by pumping brake pedal
-reset ECU
-NEW CAT

-New Coils helped out a lot with acceleration hesitation...
-Most recent CEL is p2096 "system too lean" bank 1 before Cat Converter and something about a fuel line, had to clear that because I needed to put the new battery in.

Again, car works great in the morning and night, but only acts up during the afternoon when it is very hot outside.

UPDATE: 6/7: ok, the car seems to be running better, it still will lose rpms and stall if I drive it awhile and it gets hot, but not all the time now. My problem is that I keep getting an annoying p2096 CEL code which is a system too lean bank 1 before catalyst. Could this be the o2 sensor? Could a faulty o2 sensor cause stalling and rpms drops when the engine gets hot? I have not installed my new fuel pump yet.

UPDATE: 7/9: Car had it's VDI solonoid harness fixed, but taht did not fix any problems. Car still had problems when hot. Had a mazda technician drive the car with me and it almost stalled on him, except he put it in neutral to save it by revving the RPMs. Car is at the dealer.

UPDATE: 7/20: Dealer finally decided I need a new CAT after the tests failed miserably, once they had removed my aftermarket header and replaced with the stock header. The aftermarket header was not allowing for proper cat test results and was actually making the cat pass its tests. I will post back once the cat is installed.

UPDATE: 7/20: The car needs a new cat. If anybody out there is experiencing my problems, make sure to get the cat checked out.

VERDICT: 7/26: Car needs new engine. After cat replacement. Car still gave misfire codes and the dealer is now replacing engine for free.

----Video----Here is a video of my RX8 stalling at idle in park on a hot day after driving for 30 min. The whole video, the car was vibrating a lot although you can't tell that. When the car stalls, all the indicator lights come on the right side and the oil gauge drops down. Almost impossible to start immediately afterwards, unless you crank and crank and crank...

http://www.youtube.com/watch?v=qlK9Vk6_dCE

SEAFOAM: (no audio)

http://www.youtube.com/watch?v=IaSOKmyWJMo

This is an automatic btw.....

Have a member from the club in your area look at it.

Could be coils, CAT dead engine, bad battery, several things even the plugs if installed backwards.

I have a manual that drops below 1 at Idle and gets a little rough though it never dies, I know that battery is good so I kind of assumed that it's coils (it also has some issues starting). I haven't checked them yet because I don't have the space or tools at school but theres a pretty good DIY if you use the search feature. I plan on doing it one of these weekends...

I really hope it's just the coils...

^...............if you wait too long, you will quite possibly have more expensive issues down the road.

To both of you guys............it could be quite a few things like Razz1 mentioned, but you need to start the process of elimination.

We need quite a bit more info if you want us(or anyone) to give you ideas on where to start, but Razz1 hit most of them.

adamci24..............you got the pdf on how to check the coils out?

How long they been in there?

I also assume you have no CEL(check engine light on)?

all i gotta say is take it in to the dealership i had the same problems and well now i gotta new engine .... even tho i hate the stealership they actually helped in this situation ...

The CEL came on yesterday randomly when I started my car. The car ran fine all day yesterday so I didn't take it to the dealer, but today the CEL was still on and the issues I talked about above happened. If I remember last month, when I had this stalling issue, the CEL came on. I left the car off for several hours and when I drove it again the CEL was off and the car ran fine up until today. I'm no expert but it seems this is an ignition problem (maybe coils) with the CEL popping on during ignition. I will have to take off a coil and look at it. I will replace them tomorrow and see if there is an improvement. I just baought this car used from a Mazda dealer, it has 56k and I'm
not sure when the coils were changed last.

Would be very, very useful to go get that code read somewhere like Autozone or Pepboys. Most Autozones will read it for free. Find out what it is and it should help narrow it down a lot.

If you have a meter and know how to use it, then that pdf I attached above would be useful in checking the coils.

If you add your location to your profile, you'd be suprised as someone local might be able to help you out with reading the code and/or helping determine what's wrong.

Check for dirty or ungrounded MAF sensor. Recently had similar symptoms after getting my car back from the dealer. They didnt tighten the MAF screw.

Check simple (cheap) things first.

Where is the MAF sensor located? Sorry, I just got this car so I'm not completely familiar with it yet!

Could be you SSV as well...of it sticks open the car won;t run for shit ...and it's a common problem on automatics if they are driven carefully ;)

In the intake tube. Clean the ground pads that contact the tube. Ensure the screw are properly tightened. Ensure the O-ring is not broken.And DO NOT touch the wire wound resistors inside. Spray clean the MAF using MAF cleaner or brake cleaner. You can clean the IAT sensor (brown lollipop) gently with a qtip and some rubbing alcohol.

http://garx8club.com/gallery2/d/10872-2/MAF.JPG

Ok an update:

I went to Autozone and had them test the CEL. 3 errors had to do with the MAF, and one had to do with a large emission leak?? I went and installed new coils....I also removed and cleaned the MAF sensor with the MAF cleaner. Had the battery unplugged for all this so the CEL went off. The car started up great, and drove extremely better, with fast acceleration and right now there is no CEL. Just waiting to see if it lasts like this. But wow what a difference in acceleration with these new coils....

I would doubt that you have the leak fixed...it won't show up for a couple of drive cycles..

It will run fine with the emissions leak.......unless it is a vac leak as well....but it will throw an annoyong CEL

Well, let's hope he didn't hear right, or they didn't say it right and that it's just a P0442 Evap leak........and we know that would most likely be the gas cap. Make sure you turn it enough to hear a few clicks Adam. Glad it's running better! :Peace:

In case it's not fixed and the CEL comes back on, try to have it read again and tell us what the code is, the actual code, not what they say.
Oh.........go ahead and look around the engine bay at all the hoses and where they connect. They all tight and not cracked, or have not fallen off?

Thanks for all the help guys...I'll check the gas cap, and hoses...and wait to see if the CEL comes back on. The guy who did the test said the emissions things not a big deal but could be down the road...He suggested I go to a place to get it fogged out I believe he said.

UPDATE: So I replaced the coils a few weeks ago...It fixed my acceleration problems and the car ran great for a while...Then, again the car stalled at an intersection, total loss of engine power. I also noticed that the car had trouble starting when the engine was hot, especially on hot days outside. The check engine light came on again and it was read as a ""secondary air intake sensor malfunction" which again is probably the MAF sensor. I still have the AEM CAI in the car and cleaned the MAF with the official MAF cleaner.

This morning I took the car to my local Mazda dealer. Explained the issues I've been having, and they are going to look at the car today and let me know tonight what they find. The CEL was on when I took it in...The service rep had quoted me $125 for the initial fee to look at the car. I didn't say anything about it, but shouldn't they at least do a compression test and see if it passes or fails before they start charging me money on something that the warranty might cover? I have a feeling they will blame this all on the AEM CAI, which I could understand for some of the rough idle, RPM, maybe stalling problems, but the AEM shouldn't affect the cars hot starting problem, correct? I plan on putting the stock intake in the car after I receive the parts that connect to the main air box, which I don't have right now (just have the airbox).

I will update agin when I see what they say tonight...I just want a compression test done to see what is up with the engine, and if that is one of the problems alongside the AEM. I have a 2005 with 58k BTW.

Thanks guys....

i bet messed up CAT,

Ouch hot starting problem, could be low compression

i wouldn't have left your intake in the car when you took it to the dealership, if they are a picky place they might not give you your engine under warranty if that happens to be the problem.

Yea this could be a loss of compression. Try get them to pay for the compression test.

I had no choice, considering the car was bought with the AEM, and I only have the stock air box, not the connector pieces......I printed out the service bulliten # 01-014/08 "lack of power" to bring with me as backup. If they say it is the intake, then fine, I will get the needed parts to put the stock back in, and I know that will not fix the rough idle and hot start issues, then they have nothing else to blame considering the car has an immaculate carfax service history with one dealer, and the plugs and coils have already been replaced recently...I will find out in a few hours hopefully....

Your engine is bad.

Dont let them blame the intake, tell them Mazdaspeed sells the SAME EXACT F-ing intake, the only difference is the Badge on the Intake tube. if they still say its different. Send me your pipe I send you mine. and bring it in again, just to shut them up.

That sucks that you didnt have the stock one. If im not mistaken (which i may be, and if so could someone who knows more correct me), but they dont neccesairly think that the intake is whats malfunctioning, but may try to say that the intake is the reason the the engine is malfunctioning. They would then void the warranty claiming the intake caused the problems.

Like i said only if they are picky and dont feel like putting a new engine in for you will they do this. I have not run into this situation but from what i have read on mazdas site, they are pretty picky about aftermarket parts.

edit: and like ny said dont let them blame your intake, we all know thats not the problem but if they are in a bad mood they may try

Update: Ok just got off the phone with the service rep...He said the CEL was an intake error saying there is a blockage. Basically they are blaming it on the AEM. They want me to put the stock intake back in it. I have the stock airbox so they want me to buy the other pieces necessary to install the stock intake. They also said that the spark plug wires are arcing...and want me to buy new wires. He never mentioned anything about a compression test or the engine. I brought up the hot start issues and how that has nothing to do with the intake and he agreed and said they have to see if the stock intake and new wires fix the stalling issues first and if there are still problems, "they would go from there"...He said that a compression test cost $300 to do because the RX8 is very complicated to do a compression test on compared to cylinder engines. --$300??? He did say they have replaced a couple RX8 engines at their dealer before.

I know this car will still have hot start issues after the new wires and stock intake... and I can't see myself spending $300 for them to tell me, yup the compression test failed, new engine...

I feel as though they noticed my car has 58k, and don't want to say "new engine" because then then I would get one for free, where as after 60k, the powertrain warranty is over and I would have to pay over $500 for the other engine parts needed to be installed...

What should I do?

Jesus H Christ...So I get to the dealer, and the service rep was actually very nice. He said that the plug wires were arcing, and that they should be replaced before anything else. He also recommended I go back to the stock intake. I purchased the wires there and will install them myself tonight. I mentioned how my car is almost over the 60k powertrain warranty, and they guy looked at me with a blank face. I had to have him look it up because he denied there was a warranty still on my car with 58k.

After that, I expressed my concern that I don't wanna play "swap the parts" game and find out that the engine is bad after I go over 60k. He agreed and said I could have a compression test done for $280. If the test passed, meaning the engine is good, I lost $280 dollars. He said if the engine fails and I need a new engine, then Mazda would cover the engine and the compression test. He said that he doesn't think the engine is bad though because car never gave any Misfire codes, and the technicians did a test drive successfully. He then brought in a technician who thought he was the cats ass to ask if the AEM would affect a compression test. He said no. He then turned to me and said it is not your engine, it is your plug wires. "Are you trying to get a free engine out of this or something?" I looked at him and said, "If it is bad, the yes i am."
I tried to explain to him the hot starting problems with the excessive cranking, and he says how do I know what you mean by excessive cranking, I wasn't there. I don't know."!!!

So I ended up getting the wires, to see if they would solve the problem...

ON MY WAY HOME FROM THE DEALER: The car stalls in the middle of an intersection AGAIN, and then after cranking the engine 4 times for several seconds, it finally kicked on and I pulled into a parking lot, when I put the car in park, it stalled again! I called them up immediately and they said to just get home and change the wires and see what happens in the morning.

The factory plug wires are NGK, very good quality. I've NEVER seen a set of stock NGK plug wires go bad on any rx8 or rx7. Ever, in 10 years. To "arc" it would require a cut in the wires or boots.

Bottom line, as Ive always said, the number one rule of rotary troubleshooting is COMPRESSION TEST. You should have taken it in there and said you suspect low compression, and specifically asked for a comp test. IF they want to charge you for it, fine...if it passes. IF it fails, then the comp test and the engine replacement should fall under warranty.

In my opinion, the only issues prone to cause stalling on this car are the engine compression, plugs, or gummed up throttle body blade. And the only issues likely to cause hard restarting are engine compression, coils, plugs, starter or battery.

You can use that information to make your own cross reference list.

UPDATE May 28th: So I replaced the plug wires, put back in stock Intake, and the car still stalled on me. Lost power with very very bad idling. Took it back to the dealer, had them do a compression test and check the CAT. They said the compression passed with 7.1 on the front rotor, and 7.6 on the rear rotor. He said that was above average. He also said the cat was clear and fine. They took it for 2 road tests and could not get it to stall. Said it rode like a champ.

I'm going to pick it up now. The only thing he said it could be now is a bad fuel pump. Now lets see if it will stall for me again lol. Any ideas guys?

"In my opinion, the only issues prone to cause stalling on this car are the engine compression, plugs, or gummed up throttle body blade. And the only issues likely to cause hard restarting are engine compression, coils, plugs, starter or battery. "


RR.......not trying to pull your chain(and let's be clear..........it's not applicable in this case), but can't a clogged CAT give stalling issues?
I think I've seen it caused by faulty coil(s) as well under heated conditions.

Sorry for the threadjack Adam.

I guess my statement was more geared toward "stalling at idle". Yes, I suppose a badly clogged cat could cause stalling (severe loss of power) at speed...as could coils or a fuel pump. But I'd call that "severe loss of power" and not "stalling" so I guess it depends on what your definition is.

Am I missing something here. You have a 60,000 mile warranty on the "Powertrain". Yes.
But you have a 100.000 mile warranty on the engine block and all internal workings.


Might I suggest a Seafoam on the engine. I am curious as to your driving habits with the car. Do you drive in AT mode or in Sport/manual mode?

Generally the symptoms you describe are related to a bad engine/low compression. Did you ask to see the compression test results?

Ahhhhhhhhh..........okay!

It is in AT mode. I usually don't drive it too much in manual mode. Yes the dealer gave me a copy of the results. They are in the car right now, but The standard for the front rotor was 830, minimum was 680. I had 710. The rear rotor was similar, just above the minimum, or "failing". So I did not fail the compression test. The car only loses power, or stalls, when I am idling. And it is only after the cra has heated up for awhile. I know it is about to stall, when the rpms go from a smooth 900 to a rough 600 down to a really rough 400, then boom. Nothing. Then I have to let it cool for at least 20 min before it will start again.

The dealer wants me to try to bring it in when it starts acting up so they can connect a computer to the car and monitor it as it stalls...It is hard to guess when it will happen though. Also when the car is put into park the rpms fluctuate between 500 and 900 really fast.

Also, just ordered the BHR fuel pump upgrade. When I get it, I will install it and see if that fixes my stalling issues. ....

Try driving it in Manual mode for a while. This is a rotary so it's not afraid of rpm's. Drive it up to 5000 rpm before you shift into the next gear. Take it to the redline getting on the freeway a couple times. Do this for a couple days if possible and see if it gets more noticeably better or worse.
You can build up carbon by driving in Auto mode. Lets try and get rid of some of that.

I will do this...Thanks.

Drove the car from work in Manual mode the whole way home, shifting between 5k and 6k RPM. Car did not stall on me. It was only a 10 min drive, and it usually takes about 25 min of driving before the idle takes a dive and car stalls...I will seafoam the car tomorrow on my day off as I wait for the BHR fuel pump...The only other thing I forgot to mention, was the dealer said they had an error with the VDI...The error was not there the other times I brought the car in with this problem, and he thinks the error could have been tripped by the stalling itself and trying the excessive cranking to get it to start afterwards.

OK, Just finished the seafoam process. All I can say is there was twice as much smoke than any other seafoam smoke video I have seen on here. It was ridiculous...The car stalled twice while I was revving it up and down to clear the smoke.

After the smoke was clear I took it out for a spin and the car felt a lot better, and smoother. After driving it for 5 min, I took it back home, and the car stalled again when I had it idling right before I turned it off. Tried restarting it, and it just cranked like usual. I cleaned the MAF and pumped the brake 20 times to clear whatever that clears, and now I just have it cooling down.

-So, the car is still stalling with a very rough idle after the seafoam. Same exact symptoms as before. Rpms "hunt" between 600 and 1000 while the car is in park, and will eventually stall after idling for a few seconds like that.

-Fuel pump is coming in the mail next week, maybe that is the problem? I don't know what else.

I guess it is possible that a fuel pump could cause your stalling at idle after it gets hot...if you had means to measure fuel pressure then you could find out for sure. Normally though, lack of fuel pressure will show while driving at speed under load, and not at idle...it takes very little fuel to idle, so even if a pump is only working 50% the idle should remain unchanged.

Have you checked or cleaned your throttle body yet? I have seen some nasty THICK buildup where the plate meets the body. The plate is set from the factory with a given clearance to the body, allowing a given amount of air through the crack, this air is necessary for a steady idle. When the carbon from intake reversion, and oil from the crankcase ventilation/overflow hoses get spit into the intake, it forms a pretty thick gunk that fills in much of the factory clearance/crack, allowing less air in, and causing issues idling. The drive by wire throttle cars (such as my denali, and the rx8) are more so suceptible to this in my experience. When I bought my truck it had 67k miles and it idled rough and hunted until I took the TB off and media blasted the inside of it to bare metal again, and it's been perfect ever since. I usually do this for the rx8s that I work on as well. Even if you just use sandpaper and carb cleaner, it is effectively free to do, very easy since it is right on top, and let's face it...it won't make anything worse.

So I would like to see fuel pressure checked when the stalling condition occurs, and also the throttle body cleaned to bare metal between the blade and body.

Ok, thanks I will look at the throttle body tomorrow...Also I did notice today, the car was very hesitant to accelerate in 3rd gear around 40mph. I would push the pedal down and the car did not want to accelerate past 40 mph. It was like i was driving some crappy car that had no power behind it....

UPDATE: 6/7: ok, the car seems to be running better, it still will lose rpms and stall if I drive it awhile and it gets hot, but not all the time now. My problem is that I keep getting an annoying p2096 CEL code which is a system too lean bank 1 before catalyst. Could this be the o2 sensor? Could a faulty o2 sensor cause stalling and rpms drops when the engine gets hot? I have not installed my new fuel pump yet.

I am having similar symptoms. When the car is completely warmed up and has been driven for at least 25-30 minutes, the car will idle very low (approx. 600-700 rpm) and may or may not stall when in neutral at a stop. I have a 6 sp manual transmission, and the engine has 88,000 miles on it now, and had 84k when I bought it 3 months ago.

I have not tested to see if temperature plays any affect (driving for 30 or more minutes on a cool night to see if I can replicate it), nor does this seem to happen every time I drive. I do believe it has been in mid afternoon on warm days the couple of times it has stalled on me, but I haven't kept a diary log of it or anything. And once it stalls, it's going to stall all day until whatever variable is changed and the issue is temporarily relieved.

Based on the information from this forum, I ordered new plugs, wires, and coils to start my troubleshooting journey. I figure I need new ones anyways since I have no idea when the previous owner(s) changed them last. Everything should be here by tomorrow and I should have them put on by the end of the week.

I hope we can both get this fixed, I am concerned with wtf is going on :scratchhe

Yes, and it hasn't been a common problem but maybe it is becoming one.

I also wanted to note that when the A/C is on, and I am experiencing these conditions, it is almost like asking for the engine to stall when you stop at that light or traffic stop.

Turning off the A/C, for me, has always fixed the stalling issue I was experiencing at that moment. However, it will still continue to idle very rough and at a very low rpm range (~500/600-700).

Has anyone here tried drilling a SMALL hole in the throttle blade? About 1/16" or so should do the trick, at least initially. I've heard of some of the LS v8 crowd doing this when they do a cam install or some other mod that results in a rough idle, on the cars with the DBW/non adjustable throttlebodies. The PCM will try to correct for the extra airflow to a degree, but it may be just enough of a tweak to help you. And, if it doesnt work, a tiny dab of sealant or jb stick-weld on that hole will return you to stock.

Your theory of a clogged throttle body seems very likely to be the cause. I am going to take it off and clean it and report back. Thank you :Kill1:

Yes, my problems are ONLY when the car heats up around 5pm on hot days. It drives fine at all other times. I am only getting a p2096 CEL...I have an auto, so I'm never in neutral, but it will happen in drive and park. Yesterday it happened again, the rpms pumped really fast between 500 and 700 and the car shook and vibrated. I have no idea why it does this only when it is hot. When I turn my AC on, the rpms actually increase and stabalize in my case...how much is an o2 sensor for bank 1? Any DIY out there? I'm getting very frustrated with this car. I feel like an idiot inbtraffic when my car stalls. I would just like the dealer to fix it but I don't have the money they are going to charge me for all the tests...

Only things left I can think of are:
vacuum leak
fuel pump
o2 sensor

my throttle body opening is very clean from what I saw.

Kalne, if this helps you out let me know exactly how you took it apart and cleaned it. We are obviously having the EXACT same problems...it puzzles me why it only happens from 3pm-5pm on hot days. I'm in buffalo, so it is not very humid, but it seems like the air density at that time of day is affecting something with the intake and sensors, because my car has stalled over 5 times, only at that time of day.