What was found
DURING NR 1 ENGINE START EGT INDICATION BLINKED, AS IF IMPENDING HOT START. START PROCEEDED NORMALLY, EXCEPT N2 SLUGGISH TO INCREASE. EGT PEAKED AT 595. AFTER START, WITH BOTH BLEEDS & PACKS ON, AI OFF, LEFT DUCT PRESSURE INDICATED 6 PSI, RIGHT SIDE 18 PSI. GROUNDED - YES. REMOVED & REPLACED HIGH STAGE REGULATOR REF AMM 36-11-07 OP CHECK GOOD. RAN BOTH ENGINES NO MORE DUCT SPLIT, UTILIZED FIM 36-10 TASK 804 AS REFERENCE FOR TROUBLE SHOOTING.