What was found
PHX - FLT 2164 - AIR TURNBACK. ON DEPARTURE ROLL, AIRCRAFT REPORTED FLUID COMING FROM NR 2 ENGINE, NR 2 OIL GAUGE SHOWED 3 GALLONS DROPPING TO 1 GALLON. REDUCED THRUST ON NR 2 ENGINE AND RETURNED FOR NORMAL LANDING. OIL TEMPERATURE AND PRESSURE REMAINED WITHIN NORMAL LIMITS. AT GATE, FOUND OIL CAP LOCKED AT NR 2 ENGINE, BUT NOT SEATED. FOUND CAP TO BE BAD. REPLACED CAP AND SERVICED ENGINE OIL, RAN ENGINE, OPS NORMAL. (X)