Diagnostic Aids
WARNING: This page is about a different car, the 1995 Oldsmobile Ninety-Eight and 1995 Buick Park Avenue. However, it is still accessible from the selected car via links, so may be relevant.
Check signal circuit for a intermittent open or short to ground. Also check for proper installation of PROM. If knock sensor circuit is routed too close to secondary ignition wires, it may induce a voltage and cause a false knock signal.