2004 Nissan Xterra Knock Sensor Location. Cheap ebay china ones will more than likely cause you issues down the road and it's not worth the small amount you save. There is no access to it without removing the upper and lower intake manifolds.
You can get one at ace hardware its m6 x 1.0. This issue is still open for us, since that's. It would drive just fine, but when left off for an extended period of time (overnight) it would drain the battery.