To start off, I have a 2004 RX-8 m/t. I have the BHR ignition kit, had my spark plugs changed last year (~7000 km) an exedy clutch and BHR Flywheel. The car just turned onto 83 000 km. I premix the car sometimes as well with Amsoil Interceptor and I also use Amsoil 0-w30 synthetic.

Alright, so this is my first problem with the rx-8 after many years...
First off, I was driving the other day and everything was fine, car feels fast as it always does. I then went to work and when I was done I drove the car after ~10 hours. Everything was fine, but after 7k rpm, there's just no power. Feels like it's 30whp down after 7k. Also I noticed a serious hesitation when I revved the car in neutral... It's weird, it would pause at 7500-8000rpm and then go straight to redline, but if I back off when it hits redline and floor it again the hesitation is gone. Also, i noticed a random hiccup in power at 3k rpm when I floored it in 2nd to about 6k, I lost power momentarily and then it all came back....

So first off, I'm thinking it's my cat, only recently I noticed when I drove the car for awhile it felt real slow off the line and after serious hard driving at night I would see the cat glow, all this happened within a week. It glowed 2-3 seperate times and the last time it glowed it was off 1 acceleration run.

Yes, you could say I'm dumb blah blah blah I beat the living **** out of this car but I take care of it, change all my oils before the required time and do multiple redlines daily. But I also let the car cool off, when I hear the fans turn on when I drive I make sure to drive slowly so the temperatures go down.

2nd, I made sure my SSV valve still moves and it does, although it is slightly hard to COMPLETELY open the valve, but it's really easy for it to move halfway and no it does not stick. (thanks Jon for the SSV write-up)
3rd, I cleaned my Throttle body thinking there would be any difference, but the car just felt smoother until 7k.

So basically I'm thinking it's my cat but I'm on limited funds at the moment and really do not want some **** midpipe, I can only get it in 2 weeks.

But other than that, the car feels fine, power is good till about 6.5k rpm and torque down low is still good.
If anyone can think of anything else you are welcomed to help.
thanks.

I have a video that is being processed on youtube that I'll show you.

 

Glowing cat can also mean misfires, which in turn will kill your cat. It would probably be a good idea to get codes scanned, and check ignition health.
Good luck!

 

had codes scanned a month ago,
my ignition health is perfect and had no codes involving misfires!

 

Was your cat glowing a month ago?
Why not check again?

 

no i only noticed it happening this week.
Now I'm starting to believe it's the SSV valve and the cat

 

any ideas?

 

hey guys, just wanted to let you know it was my cat like I thought.
It was clogged real bad and the second I got to the garage to get it fixed the engine shutoff (lucky me)
just thought I would update if other's were having the same problem.
Power difference? Huge! But then again I might've had this issue for years, my car has been having start off problems and some power fluctuations when hot. Turns out my cat could've been an issue for years!

lol when the mechanic took it off, the first part of the cat was just gone, all melted and destroyed into little pieces, completely blocking the exit for the exhaust to leave haha
Must say the way this car drives now is a night and day difference, feels like new
Good news, car backfires like a mawf***a and pulls really well all the way to redline!
Bad news, it's a bit stinky lol