Loud air leak coming from this elbow
 

Will this cause the car to misfire and does anyone know the name of the part.97 Chevy blazer
https://cimg4.ibsrv.net/gimg/blazerf...31562019c.jpeg
https://cimg5.ibsrv.net/gimg/blazerf...38a14ce0d.jpeg

That looks like it could be the vacuum supply connection that supplies vacuum to the HVAC actuators and the 4wd system.

A large vacuum leak could cause the engine to run incorrectly due to the mixture being off.

To check if I am correct, follow the hose that is connected to that rubber elbow and see to what it connects. You might find some other rotten vacuum hoses too.

I have link to a page that someday I'll be submitting as a stick on how to replace those hoses on the Blazers with the 4-button transfer cases. It is similar to the ones that have the 3-button transfer cases.