I have a 2001 Z24 (2.4) 5 speed. After lots of datalogging I getting timing advance way over the High Octance tables (or low Octane tables). Is there any other place the ECU gets timing advance from? I have heard at least one of person has seen this as well, but could not answer this. They thought it could be related to EGR. My car does not have EGR from the factory. Any info would be helpful. Thanks