I searched here and found out the knock sensor is in front of the starter just above the oil pan. The only thing I found there was this:

should I unscrew this and put the knock sensor there? will coolant leak out?

 

That's it... It's original purpose was a drain hole for the coolant, so yeah when you unscrew it, just about all the anti-freeze will try to drain out. Even if you drain the radiator, you'll still have coolant in the block. So have a drain pan handy.

 

Yea...One thing that I could not figure out is how the coolant has anything to do with the fuel...

 

Huh? What?

The reason you couldn't figure that out, is because there is nothing that the coolant has to do with the fuel. There's also nothing the knock sensor has to do with the fuel.

The knock sensor senses detonation that is so low that we can't hear it by ear - it lets the ECM know that detonation is occurring, and the ECM retards the timing through the distributor. None of it has anything at all to do with fuel.

 

Man, I was on my back for like an hour trying to loosen that thing but it just won't budge. Think I'm just gonna let the shop take care of it. Ridiculous.

 

It's not unusual for those plugs to be good and stuck. I've drilled at least one of them out and re-tapped the hole.

 

but wouldn't you get metal shavings in the block?

 

It doesn't matter so much, they'd be in the water passages.