Well I have a 2004 RX8 with 34K miles on it, it has a K&N Typhoon short ram intake, and a custom exhaust...I still have my cat and resonator. The car is also lowered, now here is the question....In every gear i can hear a rattle/clingy sound between 3200 RPM to 4000RPM, after that it goes away...It only happens between those RPMs...It was also doing it before i got my exhaust put on, so i know its not that...Please help, this noise is getting annoying and i told one guy at the dealership about it and he said it was coming from the dash, but honestly i dont think so. Help please.

Oh yeah, the sound doesnt happen if i accelerate really slowly in those RPM ranges....

 

Only while driving under load? Or can you reproduce it stand still at idle?

Is the sound louder outside vs inside the car? (Rule out dash theory).

Aftermarket Stereo or gauge accessories installed? (Requiring wiring & hoses to be passed through engine compartment wall, possibly moving something out of place, yeah i know lends to dash theory).

 

No upgraded stereo or gauges, etc....It wont do the rattle/cling sound in neutral only in gear....the rattle honestly does not sound like its coming from the dash....i can hear it outside of my window more so....Also when driving next to a wall that creates a echo, it makes the rattle/cling a lot louder so that makes me think its somewhere outside of the cockpit (inside) of the car, right?....

I was just driving and noticed also when sitting idle i can hear a continuous squeak, hard to describe, it goes away at times and comes back, etc....Sounds like its coming from the bottom of the car near like the front axle maybe....hmmm....

My car is a 2004 with 34,000 miles, is it still in warranty for anything? lol please tell me yes, i can afford the payments and insurance, but not all these problems, etc...lol...

 

Depending on the month you bought it, i believe it's a 4year, 50k bumper to bumper. The owners manual lists it i think.

Edmunds guide info:
http://www.edmunds.com/used/2005/maz...arranties.html


You should contact Mazda to make sure the extended warranty offer they gave out a couple years ago is also listed for your VIN.

Sorry man, i really can't fathom what would rattle, even harmonic at those RPM's... hopefully other members can help.

 

If the noise is engine-rpm related and it happens even when you rev the engine while sitting still, it is likely a vibrating heat shield under the car. As I recall, some of the early cars had that problem. I thought there was a service bulletin on that problem, but I couldn't find one at finishlineperformance.com.

Put the car up on a lift and check out all the heat shields in the vicinity of the exhaust system and transmission. If you can, have the car running with someone in it to rev the engine to the offending rpm.
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Edit: Found the info in my collection of bulletins/recalls I referred to above. It was actually "Recall 1704B" for '04 RX-8's with manual transmission and in the VIN number range (last six numbers only provided here) ...100053-116133. And it relates to the following: "On certain RX-8 vehicles, the dynamic damper heat insulator, which is installed on the manual transmission, may be cracked, causing abnormal noise. Should you continue to operate the vehicle in this condition, the insulator could come off while driving and could pose a serious hazard to a following vehicle."

So, if your '04 VIN falls within that range, and Mazda has not done the 1704B recall, you should take it in and have it done. You can call the Mazda Customer Service 800 number in your owners manual to find out if the recall has been done on your car. Be aware that this is an old recall (Feb '04), so the local service people may not be aware of it. According to the recall instructions, the repair procedure is very involved and something you probably would not want to do yourself. In any case, it is a recall, so Mazda will repair regardless of mileage/age of your car.

 

If you haven't already, do a search for "marbles in a can" or "MIAC". There are a number of threads out there that describe something similar to what you're describing, and I hear it on my car myself. Unfortunately there's a great amount of debate to exactly what the noise is. Some say it is the intake ports rattling, while others describe it as detonation, which will eventually destroy your engine.

Only under load, and typically louder under spirited acceleration. I can hear mine at just about any RPM until the engine/exhaust noise drown out the sound.

Can't say for sure that you're hearing the same thing as the MIAC phenomenon, but check up on some of the threads to see if it sounds like your issue. You might also try a tank or two of premixing to see if the noise diminishes or goes away...it did with mine.

 

Mine used to do it. Of course, it was also throwing lean codes every day.

 

Well i took the car in today and spoke with an actual tech, pretty cool guy and wanted to help all he could. I drove it and had him hear the problem and he said it wasnt detonation and that detonation is much louder and not the same noise as what mine was doing...Then he unplugged silinoids, i guess three of them, dont know exactly what they are, and he did that to see if the sound changes and nothing changed, so he plugged them all back in. Then he made sure i had no exhaust leaks or heatsheilds rattling and he said all was good. He wants me to bring it in Tuesday when he has more time to diagnose the rattle. He also said something like swapping out my K&N intake system with a stock one to see if the sound deplemishes. He was saying how something turns on with the rotary around the same RPM range and though the rattle from that could of been intensified by my aftermarket intake system...Does that make sense? lol

 

I might have missed this............are you an auto or manual?
If auto, what he told you could make some sense......I suppose????

 

my k&n i used to have was loud as hell, but didnt make any crazy vibrations until about 6k...

now my motor is making a detonation sound if i accelerate past 7k and any time i accelerate at a low rpm like 3k in third it make a loud "miac" sound from about where the midpipe is.... gonna take it in soon and we will see if i have a bad motor or a bad heatshield or something else!

 

I have a 6 speed manual....Also this rattle has been with this car since i bought it used about 3,000 miles ago...Also the tech that was in the car with me told me my rattle is not detonation....He said detonation is a lot louder, so hope he is right, from the info, does it sound like detonation? I have never got a CEL either...

By the way, this rattle sound doesnt occur in neutral, only when its in gear...And the tech also told me that i can drive it as hard as i want until Tuesday, he said its nothing to worry about and this is the same tech that told me that its not detonation...Like i said no CEL at all.

 

if in gear and accelerator in does it rattle then when u let off and coast but still in gear does it go away?

 

If i really slowly accelerate then it doesnt rattle at those RPM ranges, and also if i let off the gas and let it rev down, it also doesnt rattle in those RPM ranges either, hope that answered your question.

 

Did you check to see if your car has had the 1704b recall? Simple to do.