As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING T/O, NR 1 THROTTLE HAD TO BE ADVANCED BEYOND NORMAL POS TO ATTAIN T/O EPR, EGT AND N2 WERE IN CAUTION RANGE FOR NR 1 ENG & N1 WAS LOWER THAN NR 2 & NR 3 ENG. DUCT PRESS ON LT SIDE WAS 30 PSI ON RT 68 PSI. AFT F/A HEARD WHAT SOUNDED LIKE A BACKFIRE ON T/O. DUMPED FUEL TO 21,000 LBS TO NEEDED WT. ON SHORT FINAL HEARD POPPING SOUNDS AGAIN. ENG REPLACED.