alright i got a 2004 rx8, the car is having a hard time reving up from 4500 rpm and up, also is loosing power on the hills and no CEL

 

thanks for the help!

 

did you check your cat maybe?

 

+1 on the cat.
Do you receive a CEL at any time?
Plugs, wire, and coils are also possible.

 

I notice that you have an aftermarket intake. Does it have an oiled filter element? If so, your MAF sensor may be contaminated with oil. You will find a thread on cleaning the MAF in the DIY section of this forum.

There are any number of things that can cause a loss of power as you describe, including low compression, clogged catalytic converter, failed coil(s), and more. I would suggest that you search the forum for loss of power threads and read them. There are many.

Also, if your engine is still covered under the extended powertrain warranty, you might want to have a Mazda tech diagnose the problem.