Weird noise at cold startup

Every time I start my car from dead cold I hear a weird rattling noise that eventually stops after the car idles back to normal, but I am wondering if this is something that I need to address because it only happens at the first start of the day and I cannot reproduce it after driving it to a shop unless I leave the car there overnight.
It starts right away and increases and becomes really obvious at around the 30 second mark for about 15 seconds and then it goes away, any ideas?? Thanks guys!!!


https://www.youtube.com/watch?v=LWujaAXbKks

 

Yes only after the overnight start and only when the car is revving higher, once the idle normalizes (after a minute or so) the rattling noise goes away (like at the end of the video) and it doesn't return until next day.

 

Yes the pennzoil platinum euro 5w-40 recommended by Ferrari, I changed the oil almost a year ago and back in March the dealer did a complimentary inspection of all the car and the technician said it had a little too much and he removed a bit.

 

I know it sounds pretty bad in the video but something as threatening can't just go away after 30 seconds and never come back until the car is dead cold again, that is why I don't believe is something that serious, I will leave the car for the annual service and have the shop keep it for a couple of days so they can reproduce it, at least is not a known serious issue (like the headers noise in 430s)

 

I will buy everyone a round of drinks if I can fix this with an engine flush, I might give it a try before spending hours of labor chasing a ghost sound

 

A very good mechanic I know heard the noise and he said it is very typical for 360s to do that noise eventually, he said the fuel pressure pump has a valve that stops the fuel flow and it has a small leak and overnight it loses all the pressure, it sounds weird until the pump recovers all the pressure to supply fuel to all the cylinders.
I am traveling right now so I don't have a chance to get it checked, I will ask the shop to take a look at my return when I do the annual service


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I will and post results

 

That's what I thought but as I said before it is really weird it ceases the sound completely as soon as the idle returns to normal, I would guess the headers will keep making noise here and there.

 

Can you please take a video and post it here so we can compare them??

 

I will bring my car to the annual service next week and to address this noise, so far I have two diagnosis of two different mechanics who watched the video, one says it could be the fuel pump that loses pressure overnight.
The other one (which I believe is the most accurate one for the type of metal cracking/rattling noise) is "the secondary air system and thermal expansion of the headers" because once they are warmed up the noise goes away cleanly and it doesn't track with engine revs.
I will know for sure next week, my question for you guys is if the headers are making noises when they are warning up does this mean they are about to fail or they just need to be adjusted??
If this is the case I really want to change the headers to an aftermarket option but I have heard the smog shops in California are failing the visual test in every single car with aftermarket (shiny) parts inside the engine bay.



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I used a stethoscope and I believe the noise comes from the left header ( my window of opportunity was pretty small)
My guess is the catalytic converter "stone" inside the header is rattling

I found this thread in *********** and it makes sense to me

http://www.***********.com/#/forumsite/21041/topics/34442?page=1

But why the sound would be completely gone after less than a minute? Do these "stones" expand with heat and stop rattling??

If the header is the culprit does this merit a header change, is this the catastrophic header failure everyone talks about?
Thanks