[Tundrafoci]

could it be the intake DSI switch? I'm not sure what RPM switches the intake manifold from long to short and vice-versa but I thought it was right around 3500RPM

 

[sleepyboy]

That happens a 5.5k rpm to 6k rpm depending on the factory tune or aftermarket tune you have.

It's most likely the cat convertor shield rattling. The cat curves right up by the intake manifold under the car to clear the cross member which is right where the op is saying the noise is coming from.

Only way to confirm it is to physically jack the car up, get under there and check it out.

 

[Sniper Focus]

Cat bracket? Those used to cause mystery rattles back in the day.

 

[tjboston5676]

i had the car jacked up when i did the video. there is not cats and im pretty sure my heat shields are gone, but after thinking about it (i also have a clinking noise over bumps, wondering if its related) it may actually be somewhere in the exhaust. maybe the v band clamps around orp. ill have to get back under it again and check it out further. just hard to find time for it

 

[petik]

I know this is a 3 yr old post but i'm curious if you resolved the issue. I found the exact same problem on mine. The motor's just been rebuilt and one of the things that was done were the poly bushings on the lower rear mount, so I am curious if it is a harmonic type noise caused by the mount - possibly compounded by an aluminum flywheel. In either case, the sounds is exactly as you describe it in the same rpm range.