mods on my evo are just greddy ti-c turboback, aem intake, cobb ap tune. for some reason when i start my car and when im in the lower rpms in 4th or 5th gear i can hear something. its really hard to describe but it sounds like the exhaust noise is cutting in and out, like im running something over every second?. i have another issue that might be normal but just wanted to make sure, when im in 5k 6k rpm i can feel the exhaust vibrating my car a lot. normal?

 

bump for solution

 

You might want to Youtube the sound or no one can understand...

 

heres the sound, finally got to youtube it. you can hear it throughout the video but i annotated the ones that sounded the worst?

http://www.youtube.com/watch?v=Y65by9xn6YQ

 

check your spark plugs and all vacuum lines....

 

what happened?

 

update: while i was at the dealer i had them check the vacuum tubes and spark plugs and they said everything was good. im about to go see if the sound still occurs.