As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE, CREW FELT BUMP AND BANG EGT ROSE TO +/- 830*C, THIS HAPPENED TWICE IN 20-30 SECONDS. ACCOMPLISHED QRH PROCEDURE. NUMBER 1 ENGINE MAX EGT ABOUT 2 OR 3 SECONDS T15 PER FIM 71-06-00 PG 106, REF L/P 4332382 TO 4332389 FOR ENG INSP PARTS CHANGES AND TESTS. REMOVED AND REPLACED BVCU, ALL ENG CHECKS AND RUNS GOOD. AC OK TO CONTINUE.