As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) UPON PRE-FLIGHT RUN UP, ENG FAILED TO PRODUCE REFERENCE RPM. ACFT RETURNED TO CHOCKS AND MX DISCOVERED AT LEAST 4 OF 9 CYL SPARK PLUGS WERE BADLY DAMAGED INDICATING THAT FOREIGN MATERIAL OR ENG PARTS HAD ENTERED INDUCTION SYS ENG REQUIRED CHANGING.