I have had an ongoing problem with my CEL. I have read many of the posts concerning detonation and have tried most everything except running a hose from the engine to a stethoscope or similar set up. That is next, but for now... I have tried timing the engine as low as 2 degrees (sensor unplugged) but it doesn't make any difference. It still sets off the CEL right about 10 psi in every gear regardless of timing or fuel pressure settings. I have tried fuel pressure from 55 psi to 48 psi. 48 seems to be the best. I have +40 injectors and three different Shelgame chips, all of which do the same thing. I am running lower fuel pressure based on how the plugs look. By the way, RN12YC or RN9YC or the Autolite equivalent, no difference. I presently have about 8 degree's initial and although the CEL is lit, i only hear knock at the high end of the rpm range. Here are a couple of questions. 1. I measured my compression ratio at 9.2:1, I have the 782 head, could this be overly knock sensitive? I have decarbonized the combustion chambers by spraying water into the intake, no help. 2. I have Wiseco forged pistons, I have heard they are noisy, could this be the source of the CEL? 3. My engine has a noisy valve train, could this be coincidently resonating at 10 psi? I'm about ready to use Roachjuices teflon tape solution or remove the CEL lamp from the circuit. Would alchohol injection solve this? Any ideas?