As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
JUST AFTER T/O NR 1 ENGINE OIL PRESSURE BEGAN RAPIDLY FLUCTUATING. RECEIVED TRIPLE CHIME AND EICAS MSG (LT ENG OIL PRESS) 3 TIMES. FLUCTUATIONS WERE BETWEEN 25 AND 44 PSI. RAN QRH FOR OIL PRESSURE LEFT NR1 ENGINE AT IDLE AND LANDED. A/C RETURNED TO ATL AFTER T/O. FLTS 4310 (X2) CX, AN EMERGENCY WAS DECLARED.