What was found
AFTER TAKEOFF, RECEIVED L ENG BLEED OFF EICAS RAN QRH 2.1.14 LEVELED AT FL360. NOTICED CABIN ALT AT 8000 WHILE 5 MIN CABIN ALT AT 9500 DESCENDED DOWN TO LOWER ALT IN DESCENT RECEIVED CABIN ALT HIGH MASTER WARNING AND EICAS MSG. RAN QRC THEN QRH 2.1.1 CONTINUED DESCENT AT 18000 STABILIZED MOMENTARILY THEN CABIN ALT HIGH AGAIN CONTINUED TO 10000 FT DECLARED EMERGENCY DIVERTED ON APPROACH LT ENG OIL PRESSURE DROPPED TO 20 PSI. LANDING NORMAL. EMERGENCY DECLARED. AFTER REPLACING N3 TACH ON WRI 77-11/1273. ACCOMPLISHED IDLE ENG RUNS PER JRH, LT BLEED OPS CK NORMAL, BOTH PACKS OPS CK OK, ACFT PRESURZATION SYS OPS CK NORMAL. REF. WRI'S 77-11/1273, 79-30/1272, 21-30/1274. ACFT OK FOR SERVICE. ORIG 07/25/24