Does anyone know what this is called in the engine bay?

Bought this truck used and a friend noticed this component and mentioned that it's after market. Is it a filter of a kind and did it need to be replaced at a certain interval?

 

It's the secondary air injection pump and its oem. The uni filter is not oem but is a solid preventative maintenance mod.

 

That's the Secondary Air Injection Pump, someone did the UNI filter mod and got rid of the crappy foam filter.

Shouldn't need to mess with it unless the filter gets excessively dirty.

 

The aftermarket UNI filter mod is a good start; even better IMO (funds permitting) is to consider something like this:

https://hewitt-tech.com/product/secondary-air-injection-system-bypass-kit-gen-2-plug-play/

I know of some vehicles that run this Hewitt Tech bypass & their owners (cough cough) are completely satisfied with it. (It is, of course, "for off-road use ONLY.")

IMO the 5-star reviews on Hewitt's site are justified.

Additional TW threads on the Hewitt-Tech bypass:
https://www.tacomaworld.com/threads...pass-kit-2012-4-0-updated-21-oct-2016.394629/

https://www.tacomaworld.com/threads/sai-bypass-from-hthewitt.785716/

 

Thanks guys!!