thanks for getting back to me snowtoy Ive checked the wiring and its good. i dont want to buy a new/reman computer for $200 or a $225 knock sensor if its not the problem. I was thinking about using a 2000-2005 vortech gm knock sensor and a acdelco ignition coil resister p#f1104 a guy on here named willard did this and left it on. I just want to diagnose the problem if light stays off i need a knock sensor if it comes on its most likely the ecu. i dont know what years it will work on i already have a knock sensor and the resistor is ten bucks at parts store ten.