Ok, just yesterday I started getting this weird metalic rattling noise when I rev my **** over 5K rpm's. Its weird, just yesterday I was following my friend to his house and I took it to 6500 rpms a couple times and no noise what so ever. I go to leave his house and when I start to get on the freeway I rev it to about 6K again a couple times and everytime it made this really loud metalic rattling sound over 5k. That was over a week ago now everytime the rpms go over 5K that horrid sound comes back.

It sounds like its coming from somewhere around the middle/passenger side firewall area. I have a AEM SRI and it almost sounds like it could be that rattling but nothing on it is loose or broken and Ive had it on for over 2 years now and it JUST started making this noise. Anyone have any ideas of what it could be?? Any input would be greatly appreciated.

 

aye.. first off, try checking all your heat shields, and where your cat connects to everything.