Engine Rattle?

[Daishi]

Hey guys what im experiencing is kind of tough to describe so bear with me. Under high loads right around 2700-2800 rpm you can hear what sounds be be a grumbling rattling noise. My current mods are Injen Intakes, Fi headers and FI catback exhaust. The noise cannot be heard under any other rpm range. Ive looked around and cannot find anything hitting anything that may cause any type of unwanted noise. The intakes are secured properly and so is the exhaust.

At this same rpm under high load there is also a somewhat dead spot in the power band, Is it possible its related to the noise? possibly.. but I hear that you get that slight dead spot due to installing aftermarket intakes. My car is currently cobb tuned and ive tried a couple different tunes from different companies and it has yet to rectify the dead spot.

Is anyone else experiencing this grumbling rattling type noise at that rpm under high loads with an Injen intake? The only thing I can think of that it is is the vvel system making some noise which is more audible due to the intakes because I remember hearing a somewhat similar noise when my civic si vtec kicked in. Thanks for any help.

btw: I only use 93 octane fuel