Where is it? The only thing I can find that might be it is just under the inlet manifold but that had the wire cut flush so I'm hoping that's not it

It's under the inlet manifold just behind the oil filter.it should have a terminal on the end of the sender
Sounds like you could be looking at the knock sensor,that has a stud coming through the middle with a nut holding it on (if that makes any sense)

Andy

[Edited on 8/3/10 by lotusmadandy]

think you will find its usually to the left of the oil pump / filter when looking at the inlet side of the block. the sensor with the cut wire is as already stated a knock sensor, although i have also heard it described as a cylinder head temp sender, either way its surplus to requirements