bought a new ej1 last month completely bone stock. so far all i've done is add a front and rear strut bar and swapped the intake twice.

originally driving the car home (about 40 miles) i never heard a thing. drove it around for a little more and i didnt hear anything..

then i dropped in a cai, i was missing the bottom bushing, but i did not think it was going to be an issue. drove the car and i noticed a rattling noise at 2400 rpms in 4th and 5th. it would sound normall, then once it passes 2400 in either gear, the rattling becomes very noticable.

this cai was temporary anyways because i needed to repaint my plastic dork. Repainted it and dropped it in. it barely fit. actually the intake mani coupler doesnt even fully mate, but it mates enough for me to tighten the coupler tie. the other end is rubbing on the abs fuse box and the middle is rubbing the abs wiring.

again, once i shift into 4th and hit the 2400 mark, it rattles
then again in 5th at the same rpms

any idea? it's a very hollow rattle, like if there was a nut rolling around behind the door of the throttle body

 

could be your transmission

 

It sounds like it could also be your exhaust. My exhaust makes a similar rattling noise at about the same RPM.

 

wow, diagnosing rattles!!! this is awesome.

i'm gonna say its your _______ mount.
or maybe your __________ shaft

seriously, get in your engine bay and tighten **** till it goes away, there's not much we can do out here on the "internets"

 

i really dont know what it is, but i dont think it's my exhaust mounts because i noticed it only happens when i step on the gas

and if it was a loose bolt wouldnt it rattle all the time?

and it's not really a rattle because the word rattle kinda implies high pitched. but it's sort of a humming chatter

 

could be the heat shield on your catalytic converter

 

i've had a broken exhaust bracket before, and that rattle never responded like this one.

this one rattles when i put the foot on the throttle, and stops when i let go. it's like something is wrong with the intake mani

 

does it rattle just in gear or in neutral also? if it does it in neutral, pop your hood, get someone to rev it to that rpm while you're under the hood diggin around...

 

only in 4th and 5th