I'm not new here or to my 8. I've read every sticky on all sub forums... twice.

2004 GT 6spd
BHR ignition
MM tune w/ AP
MS Cat back
MS Intake
Pre-mix w/ Idemitsu
65k miles on original motor

Recently while hitting the back roads hard (multiple redline runs in 1st, 2nd and 3rd gears) I'll get what feels exactly like misfires and the RPMs won't go any further. I would feel much better if I was getting a CEL but I'm not. Hell, I have a AP mid pipe in a box but my CAT is not glowing at all when I check it. Obviously I pull RIGHT over and look right under the car to check; I don't wait until I get home.

So, ideas?

My next course of action is to pull the cat anyway and visually inspect it, however if its clean (I know what a good one looks like) I'll be at a loss as to what to do next.

May just have to face the music and get another compression test? It tested at OEM levels 20k miles ago by a Mazda certified rotary tech at the dealer.

Maybe nothing will come of this thread but I know you can all relate when trying to figure out what's wrong with your baby.

 

Typed this on my tablet so please ask if you need more details.

 

Also test the coils

 

That slipped my mind, thank you. I actually have that tester you recommended.

Fwiw, this is my second BHR kit.

 

I am wondering if you are low on oil and are oil starving your engine, which can cause the engine to limit the revs aroun 7k. Were/are you around 1 quart low?

 

Interesting. Last I checked I wasn't but I'll check again. Thank you for the advice.

 

Oil wasn't the problem. Hopefully i'll be able to pull the CAT and check the coils this weekend.

 

no it won't

 

Alright, I bought the required nuts and PB blaster so i'll attack the cat tomorrow. We're expecting 2-4 inches of snow here so it should get interesting on the drive to my parents house, however their heated garage is WELL worth it...

The more reading I do I really believe its got to be the cat... either way, all the coils are being tested. Thanks again for that DIY Team, this may end up being the second time its saved me.

 

Quite a long day at my parents and the AP midpipe is installed. The coils all checked out fine.

As for if my problem is solved? As I arrived at my parents house this morning to put my car in their garage, the snow started. It didn't end until there was 4 inches on the ground so i'm staying here for the night. We'll see tomorrow once I can drive the hour home.

The cat, at least visually, looked to be on its way out. There was a big crack in the catalyst material all the way through it. This usually how they look when they're failed?

 

Seems to be solved; I can do redline runs in every gear without an issue.

I'm still a bit concerned with the butt-dyno factor.. The car just doesn't feel like it pulls as hard as it used to, however it may be the winter snow tires/wheels I put on it at the same time that I did the mid-pipe.

O and btw.. holy **** this is loud.