I'm having the same problem with mine. The symptoms:

- continues to loose power the longer it is driven
(drove recently from Nashville, TN to Bloomington IN- started out fine but by the time I got to IN, it would barely crawl up a hill)

- noise when the problem is at its worst- kinda sounds like gravel being stirred in a plastic bucket

My mechanic is baffled, and they have trouble reproducing the problem (though I don't).

Any help/ideas would be greatly appreciated.

 

Gaaahhh those idiots! My dealer also had problems "recreating" the noise, until i hada tech sit in the passenger seat while I drove the **** outta it and made the sound. They tried telling me its made by the midpipe that I put in... until I told them i put the midpipe in to replace the OEM cat which also had the unpleasant sound/powerloss during it's stay, lol

 

Search for "Marbles in a can"

 

OddDood and others - Had MSP16 done yesterday. 2 hard test drives. 2 stalls @ stops. Returned to dealer today for Lack of Engine Power test and they DIDN'T do the CAT test - say I need new coils, plugs, wires and carboned throttle housing cleaned, all which done 6,000 mi ago. They don't understand that effects only happen when causes/conditions assembled. Any suggestions out there?

 

Take one of their service guys out for a drive bud. Make them hear it, lol.

And I think I may ave a slightly different problem now... Just an observation, but a couple of days ago, I gunned it from a stop. When the sound came in after 5kRPM, it came on harcore, and the windshield fogged up... Not sure what it means, lol. But is there a valve or opening that if not covered or hooked up properly will vent to atmosphere?

 

Last time it happened to me I was going to DE. I kept pushin it until I was coming down a hill. Then I put it in neutral to coast downhill thinking I'd pick up some speed to get off the next exit. The car actually slowed down on a 40 degree slope with no brakes and in neutral. Kinda backwards if u ask me.

 

weird....mine did the same thing. For being lightweight and hardly no rolling resistance, it slows down...these cars are goofier than ****.

For all having the problem, id put the screen back in and see if that helps. It did for me. I also cleaned the plugs well with a wire wheel on the dremel.

and the gravel sound is detonation...

 

Was a common cause ever found for people reporting this?

My '04 has been doing this too. A raspy, rattle-ish, unhealthy noise that starts around 5,000 rpm, and only when the throttle is being pushed to the floor.

It's not consistent though. If it's happening on any given day, it tends to keep happening during the entire drive. But then the next day it's gone, and I'll forget about it for a week, then it's back for a few drives. Repeat.

It happened in 95 degree heat last summer, and 30 degree cold today. Car is totally stock. Coils and plugs maybe two years old. It started happening at around 70,000 miles.

I notice other people mentioning how it starts at around 5,000 rpm also, so I wonder if that's some sort of clue?

 

Update:

I installed BHR coils, new plug wires, and new spark plugs and it made an improvement. Prior to the BHR coils, the car would die at intersections. However, the car still had the raspy sound and loss of power above 4000 rpm. I finally took it to the dealer. They performed a compression check and all readings were in the 5.7 - 5.9 kgf/cm^2 range which is low. They decarboned it twice and determined that it was running well. I picked it up and it indeed did run well for awhile. But after a short highway drive the original symptoms were back.

I dropped it off this morning to have the compression re-checked. If it is still low we will be discussing our options. Presumably this will mean getting a new engine.

So in summary, if you have the raspy sound issue and you know you have good coils and plugs, the problem is very likely poor compression.

 

I will be pissed if it turns out a new engine is needed. I have an 07 motor in it with ~38000 miles on it. It would be just my luck, though. I need to decarb mine first and foremost. Hopefully that'll be enough to alleviate the issue. Though from what it seems that will only be a temporary bliss anyways...

 

The compression was re-checked. The results were in the 5.7 to 5.9 range except for one which was at 5.2 (ouch!). They were all at 258 rpm.

They asked for oil change receipts (as usual) which I don't have. I put my oil change records into My Mazda and that was good enough for them. They say that they can't find a replacement engine so I have to wait until they find one.

My dealer which is located in West Des Moines, IA said that they replaced 24 engines in 2009. That seems pretty amazing to me since there aren't many RX-8's around here.

 

Is there any definitive answer to this issue? I have less than 9k left on warranty and don't wanna spend over $1,000 for the dealer to "diagnose" (or probably not actually diagnose) a problem.

 

Please let me know as well. I'm about to trade mine in, because I haven't been able to get this problem fixed.

 

There were thoughts earlier as to wether this could be a single repeating misfire. I had codes pulled and misfire was one of them... I dont think anyone else is having this issue though. It also confuses me as I replaced plugs, wires and coils with OEM parts several months ago. I'm really debating on sending my engine out to Rotary to have rebuilt. Maybe he could see the problem if he had it apart. Idk though as my car has always had this problem (8months and going) and it has never died or failed to start on me. It always runs strong when started so i dont think compression is low

 

That's more or less the same with me. I first start it up and it runs normally. Most of my travels are on the freeway so I notice after the car warms up is typically when it starts. It's pathetic. I damn near have to drop to 3rd to get enough power to pass someone once it starts acting up. Once summer hits I'm gonna Seafoam the engine and hope that helps. Beyond that, I have no idea what to do about it, short of stacking up funds for a trip to the dealership.

 

I've seafoamed twice within a couple weeks. No help.
New coils, plugs wires. No help.
New cat/exhaust. No help.

The car runs great at lower engine temps, pulls good. But once it's up to 70+ degrees water temp or so it'll detonate and loss of power like a ****.

I'm not convinced it's an engine cooling problem since the car doesn't overheat or go any substantial amount over the thermostat opening temp. Maybe a hot spot? But i'm doubtful.

Fuel pump overheating, maybe? It's almost $750 from my dealer (not installed). So I'm not about to go grab one to try it out.

Frustrating as hell.

 

Did you do a compression test after the seafoaming?
This fuel pump assembly is cheaper and better than the one you'd buy from your dealer anyway.

 

OUt of curiosity, after power has gone to *****, do you regain some of it by driving like a grandma? If I drive carefull for 30 min or so, some power returns until I drive agressivly.

I did a 1000 mile round trip to nebraska and the car held up just fine on my return trip because I never took it above 4500rpms. On the way there though I'm guilty of maxing it out at a pathetic 115 (2004 AT), and that was enough to kill any power it had left

 

Really sounds like you need a compression test there SauerKraut.

 

I have the EXACT same problem, 2004 AT replaced engine in 07, now has 45k miles on it. K&N intake, exoticspeed exhaust, oem cat. SO annoying, hopefully we can find a fix soon

 

Hey not to be rude but i got to chime in on this. I think i'm experienced the same problem.

The Lay out:
04 gt 6spd
104k mi
Mods- K&N airfilter.
original motor.
clutch pedal just started squeaking last year

Noticed something similar to what you have all described. its like a raspy sound at plus 6k rpm or higher and car seems to not push as hard when this noise it present. here is where mo problem differs from the census so far. this only happens when the car ambient temp gauge read plus 85 degrees outside. and if the AC is on the car idles hard and dies when clutch is pushed in to coast or when car is stopped (say like at a traffic light). if and when car dies it is hard as hell to get it to start again. of if i'm rolling i can pop clutch and take off again.
the car did this once last year and my dad suggested vapor lock possibly due to bad gas cap. This year i do have a CEL and code reads loose gas cap or small evap leak. i'm going to order plugs and possibly wires tomorrow. I hope this helps i'm stumped and i really dont want to dump to much in this troubleshoot. the economy already killing me financially. But i'm really stuck on this only happens when hot out.
idles hard after heavy stop n go or high speed on interstate. and will die if sitting but only when plus 85F out. am i going crazy, i've never had a car with gremlins like this.

Please someone help. If your in the VA area let me know. Maybe can meet up.

 

Mine also idles rough when the ac is on, but I assume thats due to the added strain on an already weak engine. I put in a bottle of seafoam yesterday and the thing feels 10X better, and it doesnt make the noise any more.... but I have no illusions about this being a long term solution

 

One thing I had previously thought was quality of gasoline (Actually it was my first thought when I noticed the problem); prompting various octane boosters and what have you. I had more success using an injector cleaner than an octane booster (octane boosters didn't seem to help at all). Though using injector cleaner, it seemed the problem rarely happened (or at least wasn't as bad).

Of course I'm not going to dump an extra $7 per fill up, when it already costs $80 a week for ~300km. As it doesn't solve the underlying problem.

I doubt the injectors are "dirty", especially considering the tank immediately after (sans cleaner) would revert back to the full blown issue. I hadn't kept records of success or anything, but perhaps if you guys would be willing to try a bottle or injector cleaner to see if you notice any difference?

I'm wondering if there's something in the injector cleaner that is helping either cool or lubricate (maybe even both) the injectors (or fuel pump)? It sorta makes sense, as if the injector operates even slightly slower than it's supposed to (added heat/friction) and the ECU will be in a battle to constantly advance/retard timing. It fits with the idea that heat is a major contributing factor.

And the noise isn't a full blown MIAC (which is pretty distinctive), but it's similar in a way. I have had MIAC which I attributed to the same underlying problem, but it's rarely I get full MIAC; I always get this other stupid noise in the audio clip. Maybe we'll call it SCITBSGF (small card in the bicycle spokes going fast)

If injector cleaner helps anyone else, it's another step in the right direction i guess.

NAPA primary/secondary injectors $90/each ($360/set of 4)
MAZDA dealership primary/secondary injectors $227/each ($908/set of 4) <-- LMAOSHMSFOAIDMT

I'm convinced this is the solution! That is until we prove it wrong lol.

 

Mine only does it when it's hot (and in the UK, that's a relative term). High octane fuel stops the problem, but is expensive.

Mine's got new coil packs, plugs and leads (wires?) and a new Toyosport cat-back exhaust. Coolant temp runs 185'f, Ultra gauge says it's not running weak/lean. Compression test results were good too. Everything measures/reads/checks ok according to the manuals.

Oh, and the CAT is fine as well.

 

Is your MAF clean? Any valves that get stuck?
Check the compression again, then the fuel pump\injectors as they may play a role in it as well especially if you're over 60000miles.
Does it get better with some heavier premix? (300g\tank)?
The rear portion of the catalyzer should be checked as well, usually it's overlooked since it's covered by the front one.