hello - ive fixed a few issues with this 8 already - 2004 6 spd - everytime i start the car, it makes a real low tone garbled drowning noise, the noise goes away in about 15 to 30 seconds and engine runs fine after that.i replaced the plugs,wires,tested coil packs,new starter,new battery. the longer it sits the worse it gets. injectors is something im leaning towards now , maybe a bad cat ? - anyone had a similar issue ?

 

I know exactly what you are talking about. It just sounds a lot louder then it goes back to normal, right? Mine does it when the air pump would be running, except that I unplugged mine (because I don't have a catalytic converter, and my pump was failing). It isn't noticeable with the pump plugged in, so I'm guessing your air pump is either shot/unplugged/fuse is blown....in other words, like mine, it isn't operating haha

Are you getting a CEL? If the pump isn't working, you should be

 

Where in Florida are you located?

 

ive had the cel for a looooooong time, but ive been messing around with the car for so long, didnt bother me, i did put a straight pipe on the car b4, took it off. now im stock again. autozone read codes, said a LEAK ? - not too helpful.

 

i just watched this video - not the sound im getting - mine is a low garble, sounds like engine is gonna stall, then it slowly pushes through what ever i the prob, runs fine -

 

Yeah that's how an airpump sounds when it's failing. I'm not talking about that noise. Mine makes the low garbled noise when the airpump would be operating, but isn't because it's unplugged. Yours makes the noise only when the engine is cold, right? I'm 99% sure we are talking about the same noise, once my car cools off again, I'll get a video and upload it.

Also, CELs are important on these cars. Depends on what kind of leak, could be serious, or not. I'd bet that there's a code for the air pump in there, but if you don't have a reader, then the way we'll know is if the noise in my video is the noise you're experiencing. Mine runs fine afterwards too, it's just makes a really low raspy loud noise when it's cold and first started, the colder outside, the longer it makes the noise

 

Here's what I'm talking about, I got a video of my car today when it was cold

Cold Start Mazda RX-8 No Air Pump - YouTube

 

hmmm - sound pretty close to mine now - imma take a vid in the morning - so if this is the case, imma buy a straight pipe, and unplug the air pump ?

 

Yeah if there's no cat then the air pump is pointless so you might as well unplug it