Suffering From a Misfire? START HERE.
 

Mod edit to make sure this is eminently clear, and hopefully more Google hits.
A FLASHING CEL IS ALWAYS A MISFIRE!!!
Don't believe me? Check the list of CEL codes from the OEM documentation. The 3 misfire codes are the only ones that have "flash" in the column about what to do with the CEL.
CEL List: https://www.rx8club.com/tech-garage-...n-guide-26291/

So because of the large amount of threads being started recently regarding misfires (CEL Codes P0300, P0301, P0302), I have created this thread for any of you sufferer’s to start at. This is a list of possible problems and solutions that you can carry out in order to diagnose and possibly fix your misfire. I want to note that these are in no particular order, and that each persons circumstances can vary; therefore I encourage reading over all the possibilites and going from there. The only one in any real position is #1, as Coils/Plugs/Wires is a common, but not always source of the issue.

Misfires can be caused by many problems in different areas of the car. Some are an easy fix with little to no cost, and others are major, such as loss of compression in one/multiple rotors.

Saying that, if you think that I have missed out on something, which I am quite sure I have, then please comment below and I will add into the list as time goes on.

Issue #1: Ignition (Can Include Coils, Wires, and Plugs)
The coils on the RX8 have long been known to cause problems and misfires in these cars. With an average lifespan of approximately 30,000 miles, the plugs should be changed on a regular basis. The coils as well will need changing, possibly around the same time. If you change the coils, always change the plugs as well. The wires too can have issues with them, as well as the harness's that connect to the back of each coil assembly.

Solution #1: New Coils, Plugs, Wires
There are many different types of replacements you can obtain to fix the burnt out coil/plug issue. You can buy OEM coils, or aftermarket. ALWAYS, I repeat, ALWAYS use the stock plugs in the car. They are properly designed for the right heat ranges. Do not go aftermarket, especially on an NA car.

If you are needing new coils, please do consider that if you go with Mazda OEM, you will again be having to replace them. There are other options out there, but my favorite would have to be the BHR Ignition, created by BHR. The coil packs are known to have an almost 0% failure rate, and you should not have to worry about replacing them again. Please note though, that the plugs will still have to be replaced as time goes on. This kit although will help your plugs last many, if not thousands of more miles than if running on the OEM coils. They also significantly help reduce/eliminate the chance of flooding the engine. To check the plugs, take them out and look at them. Brown is OK, but black and chunky is BAD. If you can take out the plugs, you can tell if there OK or not. Check the coils by attaching an inductive timing light to the wires and revving up the engine. If the light blinks faster and faster (Or intensifies), then the coils should be in OK working condition. There is now a link below to a thread created by TeamRX8.

Also check over the wires with an inductive timing light, as well as visual inspection. You should also be able to tell when you connect the wires on both the coils and plugs that they seat properly. The harness's on the back of the coil packs should also be checked; it may not be likely that these are damaged, but if you find that with an inductive timing light, one coil is not producing spark throughout the rpm range, it could be coil, wire, harness.

PLEASE NOTE: If you change the plugs, wires, and coils (Which you should do at the same time), then please, PLEASE remember to place the plugs in the proper spots and the wires to the proper coils/plugs!!

Links (DIY'S):
For testing the coils, I have pre-written a procedure above, but it is also good to visit this thread:
https://www.rx8club.com/series-i-do-...-wires-222641/

For changing the coils, click the below link and read Post #2
DIY: How to replace ignition coils - RX8Club.com

Or
Suffering From a Misfire? START HERE. - RX8Club.com

For changing the spark plugs, click the link below
DIY: Spark Plug change....... - RX8Club.com

Issue #2: MAF Sensor
It is not uncommon for the MAF sensor to become dirty inside the intake. Although this may not be the current issue directly related to the misfire, it can play a significant role. The MAF sensor is for Mass Air Flow measuring, which in short helps with your air/fuel ratio.

Solution #2: Clean or Replace
For the most part, you will most likely be able to clean your MAF sensor. There is a link included with more detailed instruction, but in short, remove the MAF sensor from the intake and spray the two prongs inside of the cylinder with Electrical Contact Cleaner. Be careful to not touch the sensor with your hands, either. Note that replacing the sensor may be necessary if it is damaged.

Links (DIY's):
For Cleaning the MAF
DIY: How to clean the MAF..... - RX8Club.com

Issue #3: Dirty ESS
A dirty ESS (E-shaft) can cause a misfire as well, which is related with NVRAM (Non Volatile Random Access Memory). You can

Solution #3: Clean ESS, Reset NVRAM
Also known as the “20 Brake Stomp”, this is an easy, quick, and free fix. Simply turn the car to On mode, and stomp the brake pedal 20 times within 8 seconds. If successful, the oil pressure gauge will sweep. Please Note: You must have the up-to-date ECU flash. Although older flashes do support this procedure, only the updated flashes (past few) will give the oil pressure gauge sweep confirmation.

As for cleaning the ESS, check out the links below

Links (DIY's):
Resetting the NVRAM is provided above.

For Cleaning the ESS
tired of searching ess cleaning - RX8Club.com --- Specifically post #6

Problem #4: Fuel Pump
The fuel pump is an obvious problem that can be directly related to a misfire. Although not too common for the fuel pumps to go, it has happened to many people. To check if the fuel pump is in working order, hook up the fuel line to a pressure gauge. If the pressure is Around 58 PSI, then you should be fine in this area.

Solution #4: Replace Fuel Pump
Title states it all - Replace the fuel pump. If the fuel pump is one of the problems, or the main one for that matter, get it replaced ASAP.

Problem #5: Fuel Pump Harness
The fuel pump’s harness can also be an issue. Whether damaged, corroded or completely destroyed for some reason, it will cause the fuel pump to not act properly or at all, therefore causing a misfire. Check is the same way as the fuel pump - If the pressure is off, you may be able to check the harness for proper connectivity by either just observing it or trying some sort of grounded light method on it.

Solution #5: Replace / Fix
If the wires are broken and you want to try it, solder the wires up. But I would highly recommend replacing the harness.

Problem #6: Low Fuel
Yupp, that’s right. Low fuel can cause fuel pump issues, which can cause a misfire. (And its not good to run your car on low fuel because it makes the job on the fuel pump significantly harder).

Solution #6: Fill Up
Fill up on gas (Premium of course :) )

Links (DIY's):
For filling up your Gas Tank
How to Fill Up Your Gas Tank | eHow.com

Problem #7: Bad / Clogged CAT
Many people will one day suffer from a bad or clogged Catalytic Converter (AKA 'Cat'). This is very easy to test out - On a night, and on a safe road, take your car for a hard drive. After that, look underneath your car and see if the Cat is glowing. If it is, its clogged. Also, you may notice a loss in power or acceleration.

If this does not work, the best way to inspect the Cat is to physically remove it and hold it towards the sun / point a flashlight into it. You should be able to see through it. When in doubt, visit the dealership.

Solution #7: Gut or Replace
If you are still under warranty, you can most likely get your Catalytic Converter replaced at no cost to you. If, like myself, you are not under warranty, you have two options: Gut the Cat, or Replace the Cat. To gut it, remove the Cat (Search in DIY), and gut it by pounding out everything inside of it. Make sure you do not hit the O2 sensor!!!

If you do not want to gut the Cat due to emissions, noise, or apparent smell, then either buy a Mazda OEM one and get it installed (Looking at upwards of at least $1k), or, replace it will a higher quality Midpipe, Resonater, High-Flow Cat, etc. You can find these from Racing Beat and other companies, although I would highly recommend the BHR Midpipe.

Links (DIY's):
For Removing and Gutting the Cat (Follow Same Procedure For Installing a New one if you are doing that)
DIY: Gutting out your Catalytic Converter - RX8Club.com

Problem #8: Low Compression
Low compression is a for-sure for misfires. If you have low compression, you will get a misfire. But in all honestly, if you have low compression, a misfire should be the least of your concerns. To check your compression, take it to a dealership. It should only cost half/1 hour of labour at most, and will give you accurate results. Because of the fact that these are Rotary engines, you cannot get accurate results from a normal compression tester, as you have to check each face of each rotor for its separate values - In other words, get it done properly.

Solution #8: Repair, Rebuilt, Replace
Well, if you have lost compression, you have three (3) options: Sell the car, do/get an engine rebuild, or get a whole engine altogether. If you are still under warranty, time to visit the dealership for a new engine! Otherwise, save up around $2k for a used engine, and either install it yourself or get someone/some shop to do it for you.

For a quick-check to see if you may still be under warranty, see this thread:

https://www.rx8club.com/rx-8-discuss...rranty-147287/


Other Information
There are many preventative measures one can take to help, well, prevent misfires from occurring. Such idea's could include: Installing a catch can, replacing the coils and plugs when necessary (General maintenance), get a compression test once every year or so, reset your NVRAM or KAM when the car is running roughly, keeping a close eye on your CAT, etc.

One other thing, and definitely the most important tip of them all: Search these forums and use the information already here to your advantage. Too many times there are new threads started on topics that have been covered hundreds of times. This thread will furthermore be dedicated to everything Misfire related.

nice, hopefully newbs will check this instead of starting another misfire thread. might want to add dirty ess

Oil in the accordion.
Clean maf and install a catch can. I have an 04 and haven't had this problem but many have. post 04 or 05's I'm pretty sure you have to run the hose/line instead of using a filter cap. I'm sure someone can chime in on this.
Great thread btw.

I think this is a good start.
Would be nice to include DIY links for each (if available) so anyone reading this won't create a post or new thread saying, "I read in this forum to do this, but how?"

This isn't accurate:
To reset the KAM (Keep Alive Memory) which will clear the fuel trims, you disconnect the battery.

The "20 Brake Stomp" procedure is to clear the NVRAM (Non Volatile Random Access Memory) which is your e-shaft profile.
THIS would go with 200.mph's suggestion on cleaning the ESS.

Couple other things to add...

THANK YOU for adding this!
Too many people here don't help others through troubleshooting and have them blindly replacing coils.
This will hopefully get them thinking or at least, ask about it!

The factory service manual states the standard pressure is 29psi or more

Thanks guys, I will be adding / editing tonight!

You might add federal law to the list.

Definitely. Within 10 miles of driving after the first noticable misfire, my cat and 02 sensor were toast.

Ken

Ah yes, Federal Law. I'm from Saskatchewan so neither that nor emissions causes issues for me, but I threw in emissions anyways. And when I noticed my misfire, my Cat was gone within a few miles as well!

Ah... ok, you're probably right.
The FSM isn't telling you to measure pressure with the car running, so maybe the difference is the method you use.
Attachment 176381

Information Added, Original Edited as Needed. Links to DIY's also added.

Thanks to Jon316G, ken-x8, Ray, Chad D., and 200.mph for additional information and corrections to be made. :)

Lets just hope one day this gets stickied so next spring/summer the threads don't pour in again ;)

Will be adding more info soon. Let's try to get this stickied, the forum needs it IMHO

Great thread Fung...


I'll back Ray on this I see 60psi while running and usually drops to about 45-50 with the car off over time.


I'm right around that coil/wire replace mileage here too, gonna have to pull all that out and give the whole car a thorough once-over after I park it for the winter.

noobs not gonna cared ... they just gonna ask/repeat the same questions all over again ...

I know... but we still try. One day it's gonna change, just need to think positive! :yelrotflm

Your not running Ray's Ignition? Time to upgrade man!

And yeah, same here with the winter thing. Gonna have to get her all ready for another season in a garage :smoker:

I get misfires at high RPM

i have midpipe/exhaust
mazdaspeed CAI
new oem coild
new MSD wires
new premium plugs
injectors cleaned
seafoamed
running premix

tried to clean my ESS but cant get it out, not the same as the DIY post above

dont know about fuel pump

dont know about compression

but engine runs good, starts cold or hot, pulls strong, well, i think so...

Fung, you might want to add "loose spark plug wires terminals" to the coil issues. Sometimes it's really that easy.
Sorry if you already added that and I skipped it!

I do have mentioned to check if the wires are loose on either end. Lol I wrote quite a bit so its probably not hard to miss something!

You collected a wealth of information indeed, any noob will be spanked and redirected here lol! :)
BTW Clogged cats don't always glow... they actually rarely do and only in the worst case. The only safe way is to visually inspect it. Not really misfire related failure though :)

:rollingla well that's the idea! I just wanted to get some collective information so people can at least start here and hopefully not have to start a repetitive thread regarding misfires.

Additionally, I find it misleading in that there is no information as to whether or not the whole Cat glows? Does just the front glow? the rear? O2 sensor area only? I've noticed a red color right around the o2 sensor after a hard drive, don't have a check engine light, and don't know if this is enough information for the dealership to "check"/replace the Cat.... especially as I said there is no Check engine light indicating a problem.

Great thread by the way.... extremely informative.

it's true that the cat doesn't always glow. The points you mentioned are the most likely spots for glow.
The BEST way to check your cat is to pull down the front and visually inspect with a flashlight.
If you're having doubts and can't do the work, I'd bring it to the dealer

$$$$$$$$ :cussing: One more year of school

need help with coils!
 

hello is there anyone in south/central nj that knows how to work on a rx8 that would be willing to help me replace my ignition coils and spark plugs? i have the parts im just not good with this stuff need help...

That is true; I included the Cat information because if once begins suffering from this, it is most likely that, if not fixed immediately, there is a high chance of them burning out their plugs/ignition. It was put in for preventative measures I suppose.

And Cats don't always glow - I will definitely add this in! Thanks again :)

Well from personal experience, a large portion of the Cat was glowing for myself. Although I cannot be positive on this one, there should never be a spot glowing on the cat, this just doesn't seem right to me. Around the O2 sensor may be OK, but I have doubts. I would pull down the Cat to check it.

Thanks for the compliment as well ;)

I'll be adding this in / making sure that pulling it down is the main point here. Actually as I write this, I'm not even sure what I wrote for that section LOL. But I'll check it over, I'm sure I have this down, if not, I'll add it in ASAP.

But you could afford to go FI?? Lol on a side note, I'm still hoping to get up to 'stoon sometime to check out this setup of yours. I'm generally up there during the week for work - Possibly meet up before winter?

actually you should start here, same tool and troubleshooting technique applies to the OE coils:

https://www.rx8club.com/series-i-do-yourself-forum-73/diy-testing-all-rx-8-coils-gm-ls2-yukon-coils-sparkplug-wires-222641/

the cat and exhaust can glow red under load, unless you are getting misfire codes and/or power loss too it can be normal


.

I'm not really sure what to take from this comment... That my thread is s*** or are you adding on? :P

adding on or piling it on, same thing :lol:

Lol well then alrighty! :p:

Haha as for the Dollars to go FI I was lucky enough to have a wicked, but no life, shift working summer job which payed hella good dollars for 2 summers. That was a while back and didn't get hired back after the first 2 years because I wanted to take too much time off.... Thats how she goes I guess.

I'm cool with meeting up before winter, if you're gonna be up here you'll have to shoot me a PM.

This is very informative, but I have an issue, I replaced my pulley with the AP Pulley, and afterwards my CEL started blinking, when I went to find out the code it said it was a misfire, but I'm not actually getting misfires at all, I will try to reset the NVRAM but if that doesn't work can anyone give me some advise?
thanks

First advise is to use the Search function because you would have your answer without making a needless post because that is a well known issue

Second you need to do an ESS reset. You can search those two words and find out what it is and why.

Search the DIY thread for the Pulley install and it has details to that on it also

so on here someone had a misfire destroy their o2 sensor and cat, i have no cat but mine misfires like crazy now do you think that could be a problem, i've been at it for a month and a half and cannot figure it out. It runs fine too consistently to be compression. I'm leaning towards a fuel pump or o2 sensor. any ideas? i figure putting a walbro in won't hurt anything regardless. If its doing this and i'm not beating it how long til it were to screw up compression for good? i've checked coils, plugs, wires. all good. Didn't try the 20 stomp or the MAF tho. guess i got a lot of work to do this weekend

Well, lets start at the beginning, and see which steps you have checked, and which ones you haven't.

First off, you need a clean air filter. Having a clogged one doesn't do you any favors.

Next, you need a clean, fully functional MAF sensor. The computer needs to know how much air is coming in in order to determine how much fuel to inject.

Next, your throttle body needs to be clean, and not sticking.

Once it's past that point, it goes past all the valves in the Intake manifold, like the SSV. Those need to be opening and closing smoothly, and the solenoids that control them, need to be working properly.

Now the air mixes with the fuel, as the injectors spray into the intake manifold. All the injectors (6 for Series 1, 4 for Series 2) need to be functioning properly.

Finally, the air fuel mixture gets sucked into the combustion chamber. If the compression is weak, or there's too much carbon built up, you're not going to get enough mixture sucked into the combustion chamber.

Then the rotor compresses the mixture, and it aligns up for an Ignition firing event. Again, if the compression is weak, when the ignition event happens, the combustion forces are going to escape out of the combustion chamber, leading to a loss of power.

On that same note, if the ignition system is weak, that combustion event isn't going to take place, leading to no power being generated.

So now the combustion has happened, the rotor has turned, and the exhaust is exiting through the exhaust system. If your catalytic convertor or muffler are plugged up, the exhaust has no where to go, choking the engine to death, preventing the combustion chamber from being empty enough to allow it to get filled with a fresh air fuel mixture charge the next time it crosses on the intake port openings.

Also in the exhaust system are O2 sensors, that measure how much Oxygen is in the air, allowing the computer to fine tune the mixture even more. If these are dead, or carboned over, then the ECU can't get the information it needs to give you the best performance.

So, let us know which parts of that system you have tested, replaced, and taken care of.

BC.

well this is the most informative post i've seen. I'm gonna spend my entire friday night checking everything from coils down since my walbro pump will be here and the plugs and o2 should be an easy check. I'll let you know what i find out

Ok guys I got one for you. I got my 8 bout a year ago and desired to change the plug and wires cuz of a misfire and the person that had it before me put both leading plugs on the second rotor and the trailing on the first. When I went to change them I noticed the block was stamped with a t and l. I have searched and searched on the forum and everywhere I look both leading are on the bottom and trailing on top BUT the stamped t&l are rotor 1 leading on bottom trailing on top and rotor 2 is the opposite. I'm still getting a misfire at high rpms. I need to know if I am wrong bout the pos of the stamps and should I put the leading on bottom and trailing on top like I have seen in the forum???
Thx guys for ur help.

That's pretty odd and rare! If you compare both the leading and the trailing, one is shorter than the other. It's hard to imagine if the longer plug is sticking far into the chamber. I would follow the position as quoted below. By the way, have you replaced the coils and/or the wires?

Just to let you know what was the reason my car made misfires was my injectors were clogged. Fuel pressure was ok, new coils, new wires, new plugs, midpipe. My cat was glowing red when i had one, found out with my ap that it was running lean so i cleaned the injectors and now its running like new

Had code P0302 and found...
 

Worked through all of the great recommended items and appreciate everyones inputs. I found in my case was a failing spark plug on the lead position of the rear rotor.

Symptoms were codes at 6000+ rpm and rough idle. I swapped all the coils with plug wires around to different rotors and lead/trail port positions. The issue remained with P0302. Pulled the plugs and found the body for the lead plug on the second rotor showing discoloration due to heat.
I had the previous set of plugs after routine maintenance to compare ohm readings. I found the average 'known good' plugs measured around 4k ohms. The questionable plug measured 2.4 megohms, 6 times of the others. Put in an old one and now runs smoother without throwing a code.

Hope others have as easy a fix.

Blue taped = Failing plug

Just giving the thread a quick bump. If anyone had any other information that you believe should be put into the op let me know and I will be sure to add it in. Haven't really continuously been updating it as I would like to be.

My 04 had a misfire on 2. Changed plugs wires and coils now it says RANDOM MISFIRE. Anyone know what else I can do. Gotta get smog and won't pass cuz check engine light is on

this thread is great, wsh i had found it weeks ago i have been posting on this issue and no ones has been helpful.

I have an 04 which i picked up in limp mode, turned out the MOP was shot so i replaced that since then and still now it runs well no loss of power but i have a misfire. It switches between codes sometimes random miss other its 1 or 2 and it has a slight lul in power between 4 and 5k rpm.
I have changed maf coz it throw up codes, changed coils and plugs and leads, changed cat and o2 sensors.
I have now noticed oil in my accordian i manually moved the ssv switch and it doesnt appear stuck and i now have a code saying lean condition post CAT. to save me some work hours could anyone tell me where i should go to from here?

Also the engine was new when i picked the car up, a garage replaced it as to old engine was mixing water, and then it never ran again after until now.

His other thread is here
https://www.rx8club.com/trouble-shoo...xhaust-242428/

People have tried to help without any flaming.
He won't go and get a compression test and he has bought a cheap aftermarket catalytic.
Geee I wonder why you have a rear O2 cell.

He doesn't answer all your questions and if do get anything from him you have struggle to understand what it is he is trying to tell you.

Have fun boys

You have asked the same questions that are already answered in the thread, the cat was not a cheap aftermarket it was £450 stainless steel cat. mind you regardless of the quality of the cat once i removed the old one and put this one in brand new if the cat was the causing the missifre it would have gone away until the new one failed.

I have not had compression done as i would like to iliminate all other issues first as i can do that at home myself and for the compression i would need to go to mazda and if the compression is fine it will be a waste of time and money.
where as for free i can eliminate all other issues and make sure everything else is working. otherwise i get low compression replace the engine and not check all other components and end up with a problem again.
I have put up two threads and i get same questions over and over which are mainly answered in the op and i am then told to check coils and plugs and cat all after i have said they are new.

I like this thread as it is posted someone else who knows what they are doing and is very informative. In my thread i asked what are the possible causes of my problem not exactly what has happend.
I answered all your questions mate but you didnt even know what the 2004 231 psi model of and rx8 was? its an rx8 forum thought this would be where people would know that kind of thing?

feel free to read my thread and see that the people who have actually helped and given advice i have taken it and reported back the result the people who have asked questions i have answered them. dont be bitter just because you were unable to help it does not mean i didnt appriciate the effort but i would to get the problem fixed and not sit around waiting for you to ask more questions that are irrelivent to my problem.

thanks again for you efforts everyone.

please ignore the post by WCS any help would be good and i will always add my findings to the thread for other people to use.

*sigh*

what the F with all the idiots ... I mean n00bs ... these days ...

Bookmarked!! nice post. exactly what ive been searching for.

.....