Help with a 96 240sx

[TwinTurboByrd]

Hey, Im new here. My names Drew. I have a 96 240sx daily driver, all stock, yes all stock, haha. And I have a 91 300ZX Twin Turbo. And a 93 Twin Turbo Stealth. But no one here cares about the a Stealth ;) haha anyways. I developed a problem with my 240 several months back that illuminated a MIL. I ran the codes and got a knock sensor code. I can feel the timing being cut back when I drive the car, and it has noticeably less power. I replaced the knock sensor, cleared the code, unplugged the battery and let it sit for about 15 minutes. Did not fix the problem. Any other ideas would be greatly appreciated thanks!