RX8 R3 idle problems (video link provided)

[DionLFC]

So I’ve been having major problems all my RX8 ownership(1 year) with this same problem however it’s never been as extreme as it is now.


That’s the link to the video of it idling, the video was taken after 2.30 minutes of it idling from a cold start.

Some things to add,
New ignition system 9000 miles ago

Oil and air filter changed very recent

It was not premixed at this exact moment because of MOT (but it still does it with premix)

I have a “decat” and the O2 sensor isn’t mapped for it

0 power loss at all pulls extremely well from any RPM all gears.

Car was rebuilt a year ago.

Any help would be much appreciated im leaning more towards new spark plugs? And maybe the alleged decat is causing issues too?

Edit**
Will also add it doesn’t sound as bad on video but it real life it’s quite abit louder actually significantly louder you can hear it even from a distance just listen carefully to video thanks again !

[DionLFC]

The decat makes it more obvious (louder) but shouldn't be the cause.
There is no "mapping" required for the decat, other than removing the CEL codes that might appear if/when the PCM notices that the cat is missing.

What "ignition system" was fitted?

It certainly worth checking the spark plugs, as both a potential cause of the issue and/or a good indicator of the current mixture conditions.

It could be something as simple as a small intake or exhaust leak, or a dirty MAF viewtopic.php?f=25&t=36391

[DionLFC]

The decat makes it more obvious (louder) but shouldn't be the cause.
There is no "mapping" required for the decat, other than removing the CEL codes that might appear if/when the PCM notices that the cat is missing.

What "ignition system" was fitted?

It certainly worth checking the spark plugs, as both a potential cause of the issue and/or a good indicator of the current mixture conditions.

It could be something as simple as a small intake or exhaust leak, or a dirty MAF viewtopic.php?f=25&t=36391

Yeah i was thinking spark plugs, the system fitted i believe is a mazda OEM setup, however I will add that the car is potentially mapped to d585 coils instead of original mazda, but i was talking to RRP and he said that it cant be that as they would've fried themselves already (theyve dont 9000miles)so pretty stumped on that.

Still waiting to Run some tests and record the data to send over but like he said it would be pretty wild if its still running with them.

I did hear something about the mesh inside the filter box which could be, broken, bent or something of the sort.

cleaned the MAF quite thoroughly so doubt it could be that.

[warpc0il]

If the dwell had been adjusted to maximise the output for D585 coils then oem coils would indeed be fried.

If "oem" coils are fitted then hope that they came from a reliable source, as the market is flooded with fake "oem coils", while nearly all "oem quality" aftermarket replacements are just as bad.

Your engine could be running on just the leading coils, with both trailing coils dead, and it wouldn't notice to someone who wasn't very familiar with how the car should perform.

Did you actually clean the MAF or just the Intake Air Temperature sensor, as that a trap that a lot of people fall into.
The o-ring that seals the MAF/IAT unit into the intake is also a favourite for vacuum leaks.

and yes, the meshes on the intake can cause rough running if damaged, though that's normally more noticeable between 3-4k rpm.

[DionLFC]

If the dwell had been adjusted to maximise the output for D585 coils then oem coils would indeed be fried.

If "oem" coils are fitted then hope that they came from a reliable source, as the market is flooded with fake "oem coils", while nearly all "oem quality" aftermarket replacements are just as bad.

Your engine could be running on just the leading coils, with both trailing coils dead, and it wouldn't notice to someone who wasn't very familiar with how the car should perform.

Did you actually clean the MAF or just the Intake Air Temperature sensor, as that a trap that a lot of people fall into.
The o-ring that seals the MAF/IAT unit into the intake is also a favourite for vacuum leaks.

and yes, the meshes on the intake can cause rough running if damaged, though that's normally more noticeable between 3-4k rpm.

they came from rotary motion so I hope theyre relaible

trailing coils dead you say? does that mean theres some kind of irreversible damage caused by this or what does this actually entail.

I took the MAF? I thought it was out of the top of the air tube after the filter before the intake manifold? and just sprayed it down heavy with some MAF cleaner.

you know what now you have said it, I did potentially cross thread one of the bolts for the MAF but i thought that the one and whats left of the other would be more than enough but it couldve came more loose after a while of driving? in that case im going to need to find out what bolt size is for that but that could be a good shout thank you

im still curious about the trailing coils though if you could explain and if theres damage caused

[osman]

Have you tried cleaning the maf sensor and making sure the o ring isn’t damaged ?