If you need a CARB stick for your TRD intake as most don't come with them...
Let me know I've got some of these on the way:

So I ended up uninstalling my TRD CAI last week and would appreciate some feedback. I bought a 2019 Limited in September last year and shortly after, I bought and installed the TRD CAI myself. As soon as I took it out for a drive, there was a very loud and obtrusive rattle/vibration above ~4k RPM coming from the passenger side of the dash.

Since I installed the intake myself, I uninstalled it twice and tried to diagnose the rattle. Was something loose? Misaligned? Did I need to change some adjustment? Everything was extremely tight and I was pretty sure of my install work, so I just got used to the noise.

My 4R is a year old and 10k miles, so still under warranty, and I decided to bring it to the dealer to try to get them to diagnose the rattle. A master tech completely uninstalled the TRD CAI, reinstalled it, took it for a road test... still rattled/vibrated from the passenger side above ~4k RPM. They asked me to go back home and get my stock intake to use as a variable. Uninstalled the TRD CAI, reinstalled stock, no rattle. He re-installed the TRD CAI again and drove again... rattle/vibration was back. I left with the OEM intake installed.

The tech said that the OEM intake allows for a fair amount of flux and movement, whereas the TRD intake is very rigid. He said above 4k RPM, and especially when going WOT, the engine moves more in the bay and rubs the TRD Intake, causing the vibration to occur. Because the TRD CAI sits on the passenger side of the engine pay, it feels/sounds like the vibration is coming from the passenger side of the dash. The stock intake has more "give" so at higher RPM, it doesn't rub.

Has anyone had an issue like this with the TRD CAI? I'm decently technical, and installed/uninstalled/reinstalled it myself 3 times, the tech uninstalled it 2x and tested against the OEM intake... so I'm a little surprised that nobody else has had an issue like this? If I made a mistake with the install, I'd think a master tech could diagnose or fix it, and he had the same issues. I saw a nice jump in MPG with the TRD Intake, and the dynos showed ~13hp/lb-ft, so I'm not excited about having to take it off.

I will say, the stock intake is smoother and the noise is so much nicer, but it definitely kicks down slower and you can feel a slight reduction in oomph - not just the noise giving that impression.

Never had this issue, and I have over 50k+ miles and a few years on my unit. The only issue I've had is the cover doesn't sit well with the two clips vs the stock retention method of the filter/cover.

There aren't really any moving parts to the system other than the deltaP gauge. Could that have been rattling somehow with the spring element to cause your noise?

If the engine was moving enough to make contact with the intake, are there any marks that show this?

I don’t recall what that part is or where it sits. Can you elaborate a bit more?

On the TRD intake box there is a little pressure gauge. It's a gimmick to alert you that your filter is dirty. It has a little yellow button to reset it. You can see it in this generic photo.

Ah yes. Not sure... I had it pressed down as instructed, but to your point, that’s about the only moving part on the entire intake.

I’ll have to look over the TRD CAI parts for any sign of contact or rubbing as well. Good point.

I'm interested - PM inbound

I just cleaned my filter and I also noticed the small hole at the bottom (the one on the side is plugged already).

Can I ask you why you think it should be plugged? If the kit gave us a plug for the side hole but not one for the bottom, maybe it should be left open?
Maybe it's a way for drain any moisture or excess water?

Thanks!

I never recalled the oem factory lower air box to have any hole in the bottom. So I plugged mine, as many have done.
I guess that's an individual choice!

Let us know how it turns out!

Thanks for the prompt reply.

I haven't check the stock air box but if there isn't one there, I guess you got a point! lol

I like the TRD CAI but I'm a bit annoyed by the whistle, I might try to put some tape and see if that helps reducing it.

the whistle has nothing to do w/ the holes.. its the nature of the K&N style cotton filter. If the OEM filter fits in the TRD box, test the oem paper filter in the TRD and the whistling will stop

That's probably why mine never whistled. I used the OEM paper filter, not the TRD one......

Oh, got it. Well I just cleaned and oiled my TRD filter, maybe next time I'll give it a shot.

Great hack, thank you!

I have been wondering if my problem might have been using the stock filter in the TRD CAI air box... would that cause rattling and vibration? I feel like others have done this and I haven't seen anyone else comment on problems with rattling like I had before uninstalling.