i found it when i changed my intake manifold.

its in between cylinder 2 and 3, its an allen head plug

out of curiosity i unscrewed it and took it out, saw oil, put it back in.

just wandering what its for.

d16z6

 

is it white or have a white plug? IAT sensor.. intake tempture

 

this is just a plug. i may have been part of the casting process to help the aluminum flow. they have to plug the hole so the passages don't leak so they tapped and screwed in a plug.

that's just one theory, but i am pretty sure it has no other function than something similar to that.

you have a bigger one behind the cam gear on that head too.