knock sensor 96 I30

Hey Guys, I recently found out from the diagnostic check at the dealer, that i have a malfunctioning knock sensor. Im guessing it is mounted somewhere on the block, near the combustion chambers. Does anyone know how to replace this component, and if so, is there so much removal of other stuff involved, that i could potentially break or lose other parts in the process. Pleas consider that i am mechinically inclined, and have a fair amount of car knowledge, but i have never done this repair before. It is for my mom, and the dealer wants over 500 just for the sensor alone. Thanks.

It's in the valley between the heads. Someone with skinny hands & tools might get to it without removing too much. I know a 97 Maxima knock sensor is $167 at the dealer - but not positive it's the same

I just replaced my '96 knock sensor. I got it from www.everythinginfiniti.com for $123.06 (less shipping). I got it out okay but had to have my wife stick her hand in there and thread it by hand enough where I could use the ratchet.