If you unplug it, look/feel for wet right under where it plugs in at. If is wet, it is leaking. It can leak elsewhere but that is a good starting spot. When you do unplug it, LOOK with a mirror and light before you touch it. If you have a borescope, even better.
Another likely place is the back of the intake. If you do the intake fix, way easier to do the sensor when is disassembled. Also, do the knock sensors and harness while in there.
Last but certainly not least, create all your GMT800 vehicle info, so it is there when you post asking for help. Unless of course, you think each and EVERY GMT800 is exactly the same. C'mon man!
Just remember, I am messing with you. Don't get butt hurt about me being a smart ass!