What was found
RETURNED TO DEPARTURE WHILE AT 350 IN CRUISE, RT ENG BLEED VALVE CAUTION AND R BLEED AND R PACK SHUT DOWN. CYCLING VIA QRH FAILED TO FIX. SHORTLY AFTER THE SAME HAPPENED TO L ENG BLD VALVE AND PACK. DECLARED EMERGENCY AND DESCENDED TO 10K AND LANDED. T/S PER FIM REPLACED (R) ENG 450 TEMP SENSOR, FAV TEMP SENSOR. REPLACED (L) ENG REV FLOW CONTROLLER AND HP CONTROLLER RAN ENGS OK FOR SVC.