Rattling Sound on high RPM OH..OOOH?
 

My rx8 has 108K miles on it. Im getting a horrible lack of power on acceleration. It starts to rattle at around 5k RPM. When the car is cold it seems fine but when it gets to temperature i start hearing those rattling sounds. I just had the SSV valve replaced last week cuzz that code P2070 came up earlier. Now the check engine light is on again (not sure for what yet) and the rattling sound has been there still after they replaced the valve. What could be the prob. I'm having a bad feeling my engine is gone. What should I do?

First of all you need to have the CEL read. Usually autozone, pepboys, advance autoparts do it for free. Once you find out the code let us know.

Not to scare you, but when my first motor went the car would run fine when cold but once it got up to temp it would run like crap around 4500rpms and i would hear a strange sound. So i took it to the dealer. After the dealership called MNA they told me when the engine was at temp the apex seals were not sealing causing spark knock. Thats waht they told me so i do not know if it was true or not. Either way i needed a new engine.

Rattling as in "marbles in a can" sound?

I had same thing....turned out that seals were shot so motor and intake manifold had to be replaced

How much that run u? Or did u have it under warranty still.

SO I got the CEL checked it was code P2096. I don't think that effects the Compression prob.