Rumbling Vibrations coming from under 2015 Tacoma PreRunner V6

My family and I have notice this vibrating rumble coming from under the truck. My sister noticed it was easier to hear the rumbling down on the front foot well below our front seats (under the glove box).

I have uploaded two videos to show the sound of me driving and the rumbling come up, and another video emphasizing the sound we hear.

Because the rumbling is more bass than treble, It's easier to hear it with headphones on and the volume up.

The sound only occurs at very low speeds or when stopping at the red light while in gear. Sometimes the rumbling vibrations are so persistent that it can be felt through the front doors and side windows. It goes away as soon as I start driving again or when in Neutral.

I am positive it is not coming from the engine as I've inspected that every time I worked on the truck (from keeping up with oil changes, the fluid drain & fills, to changing the spark plugs and PCV). The sound is originating from beneath the truck, probably from the transmission or driveshaft area.

 

Try cleaning the throttle body and check the motor mounts

 

Use a GoPro camera (or similar) to capture the driveshaft & carrier bearing while driving and see if the shake is coming from there. Possibly the carrier bearing is going / has gone bad.

 

Carrier bearing or universal joint(s).

 

So here are more videos of my brother and I trying to find the source of the sound while stopped in gear (3rd speed).
Again, the rumbling, vibrating sound that emanates through the cabin (most audible near the front footwells) only comes when the truck is in gear and stopped (i.e. stopping at the traffic light) and goes away as soon as the truck is back in motion or when shifting to Neutral, Reverse, or Park.

Here is the video on what I saw underneath the Driver side. Nothing unusual, maybe a slight vibration on the catalytic converter and pipes. Cat's heat shield seem perfect. driveshaft seem fine, carrier bearing seem ok, frame is solid.

Here is the video on what I saw underneath the Passenger side. The motor mount down there seem fine, maybe the exhaust was vibrating a bit more than the Cat.

For now I agree that I should definitely spend some time cleaning the air mass sensor and the throttle body. I bought the right cleaning fluids from AutoZone for this exact job that I was planning on doing anyways. May as well clean the cylinders with seafoam as well while I'm at it too (I'm at 96k miles on the odometer).

P.S.:
Here is another sound we heard whenever we shifted into different gears/speeds on the automatic transmission, and underneath.

 

Cleaned the Throttle Body, seemed to help a bit!

 

https://youtu.be/7JeO6jLklMg?si=NrVF0wmxlyU3bTyR

 

Hey all, changed all 3 of my U-Joints as well as the Center Support Carrier Bearing!

$75 Driveshaft Parts Driveshaft Support Bearing & Spicer U-Joints Set for Toyota Tacoma 2005-2015

Spicer replacement gear was great! (got greaseable U-joints this time, with zerk fittings).
All of the Vibrations and Most of the Rumbling went away, especially when accelerating at low speeds / in low gear/

HOWEVER, there is still some rumbling when breaking at low speeds.... I believe I should service my rear drum brakes next, and front brake rotors as well.