Was replacing my IAC today and found a missing hose/line? Was wondering which hose this is, what it’s for, and how to replace it. pictures attached for location. Any help is appreciated.

 

It is a common bypass of coolant through the TB. Unless you're trying to go back to 100% stock, just leave it as it is.

 

i believe that is the throttle body coolant pipe on passenger side of the throttle body. you should also be able to see a same pipe on driver side, i just did this bypass on my '94 auto a couple weeks ago. if you want to learn more, type in "throttle body coolant bypass."

 

Thanks a lot. good to know that it’s intentional from previous owner.

 

The bypass was made with that section of copper tubing.

 

You can tidy up and finish the throttle body coolant bypass, presumably done by a previous owner, by fitting an appropriately sized plug or blanking cap.

 

Agreed. It is coolant bypass