I got a Hypertech Fan Switch for an 88 IROC-Z 350 TPI w/AC. It's suppose to be under the car next to the back 2 spark plugs, and I see that. But it looks to be what could be a knock sensor, as it's the same plug, but there's another attachment on it that looks like a stack of 5 half dollars melted together and the sensor goes right through them.

Is that it?

Where is the knock sensor, as I've been told that might what that is.

Any help appreciated.

 

this is where my fan switch is at. between 6 & 8 like you said.

the knock sensor is further down and further to the front.

 

the real fat one that looks like silver dolars stacked is your knock sensor.. the fan swicth is skinnier and more twards the front