Was detailing the engine a bit today and found something curious. (96 302 automatic) Took a bunch of hoses and vacuum lines off so I could wire wheel the efi. As I was getting rid of aluminum oxidation from where where the front of the efi housing meets the back plate of the throttle body assembly a piece of something I thought was metal started wearing away very rapidly. It was some sort of soft material used to plug the lower of two holes on the side of the throttle body rear plate exactly in the middle, the top hole is NOT plugged. Does anyone know what these holes are for and whether or not they both should be plugged if I do not have some optional device that plugs in there?
Thanks, Phil

 

Any pics? Might help

 

I don't have a working camera ATM. the top and bottom of the back plate of the throttle body have lines going to the water pump. this is two holes in the middle of the side or edge of the back plate. there is some corresponding casting going from the holes to where the two intakes of the throttle body are.

 

I have seen small freeze plugs in throttle bodys

 

They could be freeze plugs. I was just reading in the haynes manual about taking off the throttle body assembly. I guess some throttle bodies have 2 canister purge lines. It could be that they just used the same throttle body for models with and without this so they just plugged the holes in the ones that did not have them. either way I think I am going to plug the hole. It's got to be letting "un-maf'd" air into the throttle body. Come to think of it, if it is a freeze plug and one of them is missing wouldn't I be leaking coolant?

 

It's not a freeze plug in the sense that it holds back coolant, it just looks like a tiny freeze plug. Worse than "un-maf'd" air getting in, it is *unfiltered* air, so, yeah, you should plug it up.

 

sounds like a job for JBweld.