I've recently fitted a Decat pipe that has a second sensor permanently in just after where the cat should be. I think it's what's called "cat on fire sensor". As my car doesn't need this (MY99), could i use this as an EGT sensor

 

It's a bit too far down the downpipe (and therefore too cool) to be usefully used for an EGT probe

Also, you'd need to make an adaptor to convert the thread from 18x1.5 to 1/8 BSP or similar

 

cheers mate.

It looks like its permanently attached to the pipe so changing it wasn't going to be an option, it was just an idea to see if it could be utilised in any way