Diagnostic Aids
WARNING: This page is about a different car, the 1994 Pontiac Bonneville, 1994 Oldsmobile Eighty-Eight, and 1994 Buick LeSabre. 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.