I have an 04 rx8. I've done coils, plug wires and spark plugs. Just did seafoam, cleaned ess and maf. I still get misfires at high rpm. Only when in drive, not neutral or park. What should i try next? Thank you

2004 Rx8,90k,no mods.Got the p0302 code and the engine misfires.Will change wires,plugs and coils but my worry is that now I have a small oil leak.
Car has never had a leak before,can the oil leak cause a misfire?

Are you getting a CEL code? If so, which one? Essentially, how can you tell it is actually a misfire?

In essence, it can be the other way around, but regardless, find out first if you have that oil leak. Full ignition system is a great start, I would recommend the BHR ignition system. Compression test may be in order for you, as well.

Thanks to whichever mod stickied this. I'll keep the OP updated as necessary

I had idle misfire issues due to a leak in the exhaust joint between extractor and cat.

I had a misfire issue. It ended up being because my spark plugs were shit (pics below) and the ignition coils had likely never been replaced (at 58,000 miles, bought it at 46,000 with little to no record of maintenance). :icon_no2: The engine eventually had continuous misfires in both rotors, which meant no RX-8 for a week or so. :banghead: After I replaced everything it ran like a dream. I highly recommend starting here if you have a misfire. :lol: Also my CEL codes were P0301 the first time and then when it was really bad I got both P0301 and P0302.

That "day" came in October of 2012. (when i got my RX8) This is my ...

FIRST POST

...since i chose this forum as my main source of knowledge. IMO a good choice. So here goes...

THANKS for all your trial and error, then taking the time to post and discuss.

Many times, i have been tempted to post one of those now familiar noob questions. I didn't. I searched, read, reread and couldn't come up with a question that didn't have an answer somewhere on this forum. Sometimes the details can be hard to find, but are in RX8club.com somewhere. Stickies on this forum are great for bringing those details together. So again, THANKS.

Back to my silent, but ever present, status on this forum.

By the way i read "Newbie's Guide to Modding the RX-8" by RIWWP" after buying my RX8 and it initially broke my heart. lol. My stubbornness allowed me to fall in love with my RX8.

Good to know you did the research and found what you were looking for, this forum is filled with everything you'd ever need to know

Do you get misfires even in neutral or only under load?

Check compression

Hey think i found the problem. My car misfires above 6000 rpm in drive every time and sometimes in neutral. Checked my cat and it was glowing. That's gotta be the source of the misfire right? Anything else I should check out? Thanks guys

Flashing CEL is a misfire; at this time, since you changed your ignition system, your only lead is the CAT. Check if it's clogged, otherwise, do you know if you are loosing coolant fluid?

If it's glowing, it is definitely a problem. Gut it or change it - The longer you wait, the higher the chance of blowing your plugs and coils. Plus yes, you would be getting a misfire. Just hope it isn't too late, you could also be having ignition problems and compression problems.

BUT - Those are just possibilities - FIRST place to start is the CAT

Misfire is gone on my car,think it was the coils.3 of them had the white mark .Now with new plugs,plug wires and coils the car did great on 2 drives.No oil leak after warm up but after the last drive a small amount on the floor.It is in the middle right behind the radiator.Will put the car on a lift to get a good look,but no oil leaks before my misfire adventure started.

The white mark on the coils is not an indicator of being worn out. Although if your coils have over 30,000 miles on them they are likely worn out :wiggle:

https://www.google.com/url?sa=t&rct=...43287494,d.eWU It's a PDF so make sure to open it

Thanks brothersboy for putting the PDF file,will print it out and bring with me when it's time to exchange these ones.My coils had way more(way more)than 30k,so it was time to replace them .

No problem. And the 30k is just a rough estimate. I bought my car at around 46k and replaced mine at 60k so for all I know they could have had 60k on them. And from the looks of my plugs they very well could have! :yelrotflm

I just replaced my coils, wires, and plugs this weekend- wow! Torque is back. Runs like new, idles smooth, sounds better.
I've got an '06 MT GT with 65k miles... I bought it brand new, and I shouldn't have waited this long to change the coils. It's been a bit lurchy when cold and I drove in stop and go traffic last weekend and it lost low rpm torque and would misfire when revving cold or hot, and the exhaust note sounded wrong. It didn't flash the CEL or throw a code. I stopped driving it for the week and I pulled the plugs and they were fouled. I've changed the plugs every 15-20k miles on this, probably had 10k miles on this set, and I flooded it a couple of times this winter when I didn't drive it for a few weeks and cranked it up in cold weather with a low battery.

I found that the leading coil on rotor 2 was a bit melty.

I'm guessing the new battery and ignition system will keep me going for a while. Hopefully the cat didn't get roasted, but I took it for a good italian tuneup and it ran great. The compression seems fine- I can get it hot and it won't idle sag and it fires right up. Man, it's a pain to get down to those coils. I had to pull the stiffener bar and even then had trouble getting to the bolt on the one near the wiring harness clamp.

So, my car is having a really hard time starting, and knocking and generally showing all the signs of misfiring. I found this thread - and it says I need coils/wires/plugs. Okay fine, I'm willing to replace all that and can find the instructions on how to do so fairly simply, but the only link I can find is for a $500 set. I'm looking to do it myself, I almost NEVER drive the car, but when I do, it's for something important. Can someone provide me with links for everything that I will need to do this without costing that much money!?

You can check your local auto parts store: AutoZone, O'reilly's, Advance Auto... Our forum has vendors that will sell those as parts or as a set, you will need to search for them here (i.e. BHR, mazdatrix, rotaryfx).

NGK (6701) RE9BT Laser Iridium Spark Plug, Pack of 1 : Amazon.com : Automotive

NGK (4858) ZE81 Spark Plug Wire Set : Amazon.com : Automotive

NGK (6700) RE7CL Laser Iridium Premium Spark Plug, (Pack of 1) : Amazon.com : Automotive

Mazda RX-8 Ignition Coils - Set of Four (4) : Amazon.com : Automotive

Order one coil set, one wire set, and two of each spark plug.

hey guys, i hollowed my cat the other day and im still getting the misfire. it only does it in drive now. not in neutral or park. it pulls good up until 6000 rpm. i have a code reader and it says p0300 and p2096. what should i check out next? thank you guys for the advice

i dont think it should be compression, because its good until the higher rpm and it starts fine when warm. ive check over some of the vacuum lines to look for a leak, everything looks ok to me. im kinda new to the car, ive only had it for 6 or 7 months. so far i do love it even with the misfire problems. this car is truly addicting.

have you done the 20 stomp brake pedal reset?

i tried that, cleaned maf and ess. hollowed cat, new plugs/coils/wires.

Hi there, I was going back reading about misfires, and just for clarification, it seems people think glowing cats cause misfires. I always believed the misfire
(unburned fuel) causes the cat to glow. Dealer wanted to charge me $1400 for a cat and never talked about why it went bad. I get the impression some people think replacing a glowing cat will fix the problem. The root cause is faulty ignition parts dumping fuel in the exhaust, which is burning in the cat, right?

Correct, misfires mean unburnt fuel and unconsumed air that is being dumped into the exhaust, which is ignited there and the end result is a blowtorch on the cat to some degree (intermittant to severe). Misfires cause clogged cats.


However, a clogged cat can ALSO cause a misfire, which is where some of the confusion shows up. :)

could it be my injectors? ive tried looking for some way of cleaning them, does any one have a diy for that?

Lol thanks for answering that one, I haven't been able to keep up on this thread as much as I hoped. I almost should note that in the OP (Can't assume everyone would just know some things which is perfectly fine)

See this thread, specifically post #4. Should point you in the right direction :)

https://www.rx8club.com/tech-garage-...cleaner-68828/

Tylerk,
Look up P2096 on the forum. I believe it has something to do with the MAF sensor. Even if you cleaned it, you could need a new one.

This is great info. I posted a topic asking about this about two days ago.
I was having issues with my car turning off when I reduced the speed.
Took it to the dealer and they told me rotary 1 had 2,261 missfires and rotary two had 46. I had the P0301 code.
I'm in the process of changing out the spark plugs and coils.

does anyone know a good way to check fuel pressure? i am thinking its either my maf or fuel pump. what do you guys think?
Thank you all for the help

fuel pressure gauge

thanks for the advice, i was looking into putting one in. do you have a diy for that? ive never installed a gauge before. i can handle the electrical stuff (wiring), i work at best buy in the install bay, im just not sure what all i will need and where to get the pressure reading from.

Thank you, Tyler

2004 Rx8, 112k on chassis, 65k on engine.

It seems out of nowhere, my engine is now missing while idling hot.

Throttle very responsive, power very smooth all the way to redline, just got 21mpgs on a trip to Gulfport.

Oddly, the only way it will idle flawlessly is with the A/C on.

Already checked for vacuum leaks.

I took a couple of video clips, Thoughts?

^ I never had time to get through the entire video, but short fuel trims and everything seems like its fine (confirmation from someone else here would be good), but have you actually gotten any misfire codes up?

Even with the BHR kit and newer plugs, hooking up an inductive timing light on each would be a good idea while at idle and revving slowly up to top to see if there are any misses or skips. You also say that when the AC is on the car idles fine, now I'm not sure what effect having the AC on during idle would have on the throttle body, but I assume that it opens it up a bit as it puts strain on the engine. I say this because maybe there is a bypass issue for when at idle? Seems extremely unlikely, though, if not impossible.

I will take a better look at the video tonight and see if I can come up with anything, maybe in the meantime someone else can pipe in who knows whats going on better.

No codes. Idle RPM is set 875.

I took another look at the video, and I'm not sure that sounds like a misfire problem. Initially I would have said check over the entire ignition with a timing light, which I still recommend, but after you stating how perfectly the car is running otherwise that makes me stray away from most typical issues.

I'm almost aiming towards the air intake bypass for idle, but again it should be choking more than that. Is this the only problem you are experiencing? It's hard to hear when it misses/skips a bit, but I know mine has sounded like that for some time and I'm now having to replace an engine (most likely)

Without a code up or any other issues like rpm drop, hot starts, power loss or throttle responsiveness, I would say it probably isn't something to be too concerned about. You're compression is below Mazda spec, and even when it is right below that can cause small, minimal and sometimes quite unnoticeable issues

I ran her down to empty and added 5gallons of gas with a bottle of techron a day before posting, light is about to come back on and she seems to be idling better... Who knows it could be the weather, it's been warming up. Mornings are in the low 60/50's and after noon are near 90,might be having trouble adjusting..

As soon as the "hot starts" become a issue I will be replacing the engine, and I honestly can't wait to see how she acts with a proper engine.

Temperature will affect idle and performance. Air temp and density will cause noticeable effects so yeah I wouldn't worry to much. Just keep an eye out for compression issues and just get a test done every year or so.

Must be nice to have a running car! Lol

I hit the coils with a timing light last night, all are firing. My friend is now also baffled by the issue. :lol:

Gonna be servicing the the battery terminals and some ground points today, saw a little bit of corrosion while we were under the hood.

Lol I'm almost baffled! If the timing light test went fine then only other thing I could think of (off the top of my head) would be injector issues or intake bypass... but you'd think you'd see more problems from those things...

Update:
 

After burning thru the 5 gallons of gas and having a slightly better idle, I went ahead and added a bigger bottle of techron (treats 20gal) and added 8 gallons of fuel. Just finished burning thru that, idle has gotten much better, going to fill up tomorrow back on premix.
Still not idling "perfect" but man it's so much better than before, maybe it's just carbon build up... I drive her like a bat out of hell in the mornings on my way to work, but when I get off, it's stop-n-go traffic all the way home. To give you and idea... I can make it to work in 17mins (hauling ass,4am) but it takes at least 45mins to get back home.

In a week or 2 I'll be doing a good bit of work on the car (coolant/radiator/fans/oil) and I'll go ahead and seafoam and see what that does. If no improvement I'll just blame the low compression. :lol:

Thanks for the help. :)

-Shawn

^ Glad to hear you're seeing some impovements! Lol and yes even slightly lower than Mazda specs can cause issues

Hello I am new to the club I am getting a misfire I think but any was the rx8 brakes up the higher the rpm's if I can keep it between 2k and 6k rpm it pulls hard and runs for the most part pretty good but pulling hills or flooring it past 1/4 throttle it brakes up backfiring if I could get some help it would be gratefully appreciated

Do you have any CEL's up? (Engine light). Also, I just need you to clarify exactly what you are saying here: Are you saying that when you try to put the throttle past 1/4 way, it bogs and has no power? If so, is this throughout the entire RPM range?

I would guess bad/faulty/loose secondary injector.

My s4 rx7 had a issue like that, would pull fine all the way to redline provided you stayed under half throttle. If you floored it above 4k, it would miss and backfire. Turned out one of the secondary injectors was unplugged.

Having misfires, only when engine is coldish. as in when I first fire it up until about 20+ mins of highway driving. Misfires over about 5k. And no I don't start the engine and rev the piss out of it when I first start it, I let it warm up, this a new issue. AP reader says misfire cylinder 2. It started happening after I put the factory cat back on. I have bhr coils, newer plugs, new wires an AEM cai which is clean as a whistle. Cleaned knock sensor. O2 sensor is fine as far as I can tell. Car just started to do this after removing BHR mid pipe and putting factory cat on. Kicker is factory cat is brand new. Maybe 500 Km's on it.. The day before i put the cat back on i was actually at a dealer who ran a misfire count that checked out amazing. anyway dealer is a dick now and is saying I should remove the bhr coils back to factory ones.. Which we all know are junk. So that's not happening. Not sure if anyone has ever experienced the same symptoms when going back to the factory cat. Any pointers or info would be great. Thanks in advance all!