Hi, i'm going to change the lambda sensor on my 93 wrx, I know its in the headers at the moment but rather than take it out and blank it could i just leave it there as a blank as im putting the new one in my stainless downpipe which has a blanking bolt in it. would it be the same thread size though? Also i hear its better there and lasts longer, anyone what do you think?

 

It will be the same thread size. Leaving the old one in will be ok. Probably is a better place to put it (downpipe) as the newer cars had theirs moved there.

 

no best place is in the downpipe as the pressure and heat in the headers is greater..

The newage sensor is different

you can do exactly as you suggest