That's the same sound I get but only on deceleration between 3500rpms and 3000rpms, with a slight occurrence around 1800-2000rpms as well.

Dealer thought I was crazy...any new insight into this fluttering noise, so to speak?

I have the exact same engine hammering sound on my 2013 BRZ, but it's so sporadic that I haven't gotten any good video footage. Props to the OP for some hard evidence of this flaw.

Happens during light (30-40%) throttle after a hard pull, like merging into traffic after a freeway onramp. I'll be able to reproduce it with throttle manipulation for maybe 30 seconds, but then it usually quiets down before I can get to a safe place to record.

It's worst around 3000-4000rpm, but I've heard it up into the 5k range too. Does not seem to be associated with any particular gear or MPH.

Might be correlated with ambient temperature? It was happening more frequently during a few hot weeks this past summer, and I've only experienced it when the engine is good and warm.

Problem has persisted through a couple oil changes and a high pressure fuel pump swap last week to get rid of crickets.

The dealers around me won't do much unless they can see the problem in action and it's almost impossible to reproduce on demand. Any hope of getting this fixed?

Your description is spot on. Everything is exactly how I experience it too. And yeah I've had the same problem too as far as reproducing it at the dealer. I know I can get some much better recordings. I might bring the 3d audio recordings up to the dealer when I get a chance to record them and see what they have to say. I'll keep everyone posted

mine on the way home last night.. its at the dealer now and waiting for news..[ame="https://www.youtube.com/watch?v=PQlEi87y0iA&list=UUq-kIrZDNl_GWRDNXwudCYw"]Rattle sound engine frs - YouTube[/ame]

^that sounds like rod knock to me.

Yeah... plus I'm bone stock and dealership saying if it don't look right or something they will not cover it and have to pay out my own.. trying to scare lol.. I have no fear because I'm stock and provide oil change history. .

Going to use 5 30 oil from now on.. 0 20 is too light lol.. but it's winter so it ok..

I'm sure some of you guys on here got this issue too

Just got this noise for the first time tonight. Right at 4k i can hover and itll stay consistant. First time this is happening so ill see what happens tomorrow. Car is running strong because right when i start hearing it i turned my boost all the way up and thrashed it. Runs fine so has to be something else. The only factor that has been changed is that i had 3 people in my car for the first time.

Ok, so I've got much better recordings this time around. The video is just a crappy go pro, but the audio was recorded with binaural microphones that go in my ears. This captures true binaural (3D) stereo recordings from my ears perspective. just incase any one didn't know. but yeah, its some voodoo kinda stuff. Also, got an appointment with the dealership Thursday. We'll see how it goes.

(you must wear headphones to get the true 3D effect)

Edit: youtube raped the audio. I'm re-uploading to another location
https://copy.com/qBQ0lSeoas9OFGSu
https://copy.com/JqSNPV1iHHENEg9Y

I can hear it... on nutral you hear it when you give it a Rev?

Or only hear it when the car is in gears when going?

I honestly can't hear anything out of the ordinary. These cars make a lot of noises. I don't think it is detrimental. One thing that I do know is that when you start making changes to rotating assemblies in these cars (not sure about your car specifically), the noises get amplified. Some people experience it (more often in my experience) and some don't. Before you do anything else, try sending an oil sample to Blackstone (or any other oil analysis firm) to see if anything looks out of the ordinary.

For what it is worth, when I went to a lightweight crank pulley, aftermarket clutch (lighter flywheel) and cf driveshaft, the noises definitely amplified (especially the shitty throwout bearing and especially when under load (A/C)). I have a PD blower now and a bunch of other mods and I have grown to find it acceptable. B-cuz racecar bro.

I have the same thing. I honestly believe that it is nothing more than heat shield vibration under load. I had another car have the same issue under load at certain times and had it for five years. I am going to have someone make sure the shield is nice and tight but honestly this is probably normal.

Unknown Engine Rattling (Video)
 

I thought it was probably the heat shield too. However I just switched over to the openflash header and I'm still getting the sound. But very very rarely now. Possibly something else is rattling. If it has something to do with the actual engine it probably would have failed by now as this has been happening for almost a year now

Yea I can hear it. But I think its normal. My car has same sound. these cars are just not pleasant under acceleration to listen to.

To the guys who are reporting this- any way to log knock system, VVT, etc channels and post it here? We may be able to discern whether or not it is "spark knock" or just VVT/other engine noise.

On the OFT tunes, VVT noise and resonance is around the reported rpm/load buckets (3000-4000rpm on .7+ loads)