anyone noticing loss of power occasionally on their SC X? if so, here's why. when nissan installed a SC on their trucks (frontier, xterra) they calibrated the knock sensor in with the byapss valve on the super charger. big deal right; if the engine starts knocking don't you want the boost to be bypassed? Absolutely, what they don't tell you is that if your engine knocks for some reason even once (bad gas, on it too hard, etc), the bypass valve will open, disabling the super charger. And, it will never close until you actually shut off the engine and restart. sucks i know, but it's true.