Recently installed a new AEM cold air intake and whenever i push past around 5000rpm a loud rattling sound comes from the engine, only started after installing the new intake but cant seem to find what it is. No loose clamps or bolts. Not sure if this is relavent but i was testing this on a 42 degree day here in Australia so maybe the heat played a part but still doesnt really explain the sound. Anyway would be great to here any suggestions on what the issue could be, Thanks.

Also a video of the sound in second gear:

 

I can't hear what you're referring to in the video, but by the description it sounds like MIAC.
Have a look...
https://www.rx8club.com/series-i-tec...-fixed-172684/