had a look at me down pipe the other night i have a spark plug that is broke of in a hole right at the top. what shud be there ? some sensor or some think ?

 

That'd be where the lambda sensor should go not a broken spark plug

 

Someone will correct me if i am wrong, but I believe that on the older models the Lambda is mounted elsewhere, either in the headers or the up-pipe. Which means if a decat down pipe is fitted, then there is a vacant hole for the lambda, which happens to share the same thread size as a spark plug.

(when I say older I don't know exactly how old, but defo earlier than 99)

 

I think cars older than MY97 had lamda in downpipe - pre 97 the sensor is in the headers.

 

I meant 'cars after MY97 rather than older'

 

mine is a 1995 sti so thats why i have the plug then.