Hey all, I need some help with this issue before it gets worst.
So... I have a 2004 8 manual 116k miles. when driving in 1st,2nd and 3rd gear all is normal but when I change to 4th, 5th or 6th gear @ 1000RPMs - 4000RPMs it accelerates fine but then it slows down A LOT and it goes back down to 3000RPM and it accelerates slowly back to 4000RPMs. This started to happen 3 days ago. And sometimes its does it once I hit the gas, its accelerates normal and when it hits 4000RPs and it slows down even with the gas all the way in.

 

When was the last time you've had your car serviced (change plugs and coils)? Do you notice any CEL or flashing lights on your dash?

Also, have you checked your cat converter? Sounds like it could be clogged.

 

Well i have not had a change to get it serviced just yet. I got the car about 6months ago. i will need to do soon i know. NO CEL nor any other lights. I will check the cat converter and let you know. thanks.

 

read this thread to test your plugs/coils https://www.rx8club.com/series-i-tech-garage-22/suffering-misfire-start-here-222280/
Check your cat by pulling down the front and looking in with a flashlight. Or, wait until it's dark, take the car for a hard 10 min drive, then look under on the driver side and check for any glowing.

You may even have a bad fuel pump (amongst other things). Keep us updated and good luck!

 

its could be the Cat. Ive also noticied that at 80MPH the low antifreeze light comes on.

 

That's likely a bad sensor.
Quite a common problem

 

UPDATES: work was done a while ago, havent had time to post BUT the issue was the clutch, I reported the spark plugs and wires, It did help it to idol better, tested the CAT, it passed, Mazda test it for me. clutch and flywheel were replaced for total with install from Mazda was $1200.

 

Just curious.. Can any one give a brief explanation as to how the clutch could have causing the OP's issue? Im just curious. I dont understand how the fix and problem are related. I'd like to learn.