I own a 2005 g35 coupe, 110k miles on It. Only recently, I've noticed a very strange fluttering noise if I'm going faster than 30 mph when I press the gas. Immediately after letting off the gas the noise is gone, and even if a very very slightly press the gas the noise returns. It sounds like a plaYing card in bicycle spokes, and I can't for the life of me figure it out. I also had an SES light come on and I reset it 3 different times using an ECU reset, the light would come back on a few days after reset. next time it comes on I will have the code read.

 

Check the Fuel Pressure Regulator. Mine went bad recently and was making somewhat similar noise. Sounds more like what you describe inside the engine compartment. Here is my thread with a video: https://g35driver.com/forums/general...aust-leak.html

 

I wish I could open and watch your video so I could hear if your noise is like mine....it says it's a private video though. I've got an 04 auto with 170k miles. This noise started over night and in 1 day its gotten soo soo much worse. I had a 3series bmw that made this same noise when accelerating, as it shifted from 1st into 2nd and then 3rd into 4th. I never figured out what it was on my beamer, I ended up selling it lol... But I've got to figure this out... My heat shield is making an obnoxious noise as well but its separate than this noise. I have factory airbox...everything is stock actually....haven't had her long enough to do much... there's nothing I can see causing it in the intake j r area, I'm stuck here!! I read someone said it was something stuck inside their cat bouncing around.... but I'm not trying to take the cat off this thing....what do you all suggest my next move is..... please help...

 

I would go to a local reputable muffler shop (i.e. not Midas) and have them look at it.