What is this part connected to?

That's your EVAP canister, which also contains EVAP purge valve on the earlier models that use it, IIRC. Mine is an '06 and doesn't have it. Cracked hoses there are notorious for causing EVAP codes (often P04xx format codes). It should be ultimately attached to your intake/throttle body/gas tank to recover vapors in its charcoal, allow vapors to return for burning, and/or help with holding vacuum/releasing vacuum via purge valve so the EFI system functions effectively.

 

See this thread for more hose routing, it's advised to replace the hoses if you have EVAP codes.

https://www.tundras.com/threads/project-double-gnar-p0441-and-some-missing-hoses.92422/

Pay special attention to the sticker in reply #17, which your truck (I would hope) also has.

 

Ok thank you sir.

 

I believe OP is referring to the 90 deg nipple thing in the center of his photo. EDIT - It is a vent for the canister and is correct as is except it should be turned around so the opening points down.

 

Can you send a picture on how it’s supposed to look?

 

I just looked at my truck. It’s complete as shown in your photo but needs to turned so the opening is down.

 

Ok thank you.