Found out mine went out on my 99. The gauge is all the way over at 80. Also where is it located at?

Thanks in advance

 

It's located behind the intake manifold. SHould just be a case of disconnecting the fuel line, injecotr wiring and then the intake. Then replace it.
Here's a writeup that has the instruction on removin the intake. Ignore the rest that you don't need for the valley pan.
http://www.ls1howto.com/index.php?article=18

 

It is not all that hard but you will need an oil sending unit socket (can be found at Autozone) to remove/install the d@mn thing as it is positioned in such a way as to make it tough to get a wrench on the metal hex portion at the bottom.

 

I just did it today. It took about an hour to remove the intake and an hour to install. Make sure you don't pinch any wires when you replace the intake. I wish I would of known about the oil sending wrench from AutoZone. I used a vice grip. I got my sending unit for $31 from Chevy.

 

While you are in there with the intake off check the grommets on the bottom of the knock sensors. If you have any oil coming up out of the lifter valley cover through the two large holes, they need to be reseated. Otherwise the oil will cook your knock sensors and the connectors/harness. Been there done that.