Poor DRIVEABILITY: Knocking

Check fuel quality.
Check knock sensor circuit. See CODES 52, 53 & 55 in TESTS W/CODES article in the ENGINE PERFORMANCE Section.
Check spark plugs.
Check injector circuit. See INJECTOR CIRCUIT chart in I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
Check EGR system. See CODE 71 in TESTS W/CODES article in the ENGINE PERFORMANCE Section.
Check valve timing.
Check ECU.