I just bought an 87 Grand National and have noticed my knock gauge lights are not coming on at all, only the green center light showing its on, car runs fine when cruising or slightly getting into it but once I step on it you can hear a loud knock or bang. Im guessing extreme detonation definetely timing issue. Is my knock sensor itself bad? It has an upgraded chip, performance cam and pistons from what ive been told, previous owner cant be reached, running 93 octane. Any help from my new brotherens would be appreciated