What was found
ON TAXI OUTBOUND AT SFO, PILOT REPORTED ENG NR 1 HAD N1, N2 DROP AND THE EGT ROSE TO OVER 636 FOR A FEW SEC. A/C RETURNED TO RAMP WHERE RIGGING OF VSV OF 7TH AND 10TH STAGE BLEED VALVES WERE CHECKED. ENG WAS ALSO CHECKED FOR HIGH TEMP. MASTER VSVA ACTUATOR P/N 1685MK7 AND LPC BLEED-SLAVE ACTUATOR P/N 1778MK1 REPLACED.