What was found
APPROXIMATELY 3 MIN AFTER DEPARTURE FROM SJD EN ROUTE FOR PHX THE NR 1 ENGINE STARTED SURGING BETWEEN 25 TO 30 PERCENT, TURNED BACK TO SJD, JUST PRIOR TO SHUT DOWN AS PER THE CHECKLIST, SURGING STOPPED. MAINTENANCE ISSUED MEL 73-7, COND. 1. LT PMC INOP. ON 07/13/2004 MAINTENANCE REMOVED AND REPLACED MAIN ENGINE CONTROL, ENGINE RUN OPERATIONAL CHECK WAS GOOD. VENDORS FUNCTIONAL CHECK OF MAIN ENGINE CONTROL S/N WYG1082 COULD NOT CONFIRM REASON FOR REMOVAL. ALL SCHEDULES OPERATED WITHIN CMM LIMITS. CAN ASSEMBLY WAS REMOVED TO CHECK FOR SEPARATED SPRINGS OR FOD, NO DEFECTS WERE FOUND. TEST AND INSPECTION ACCOMPLISHED IAW CMM 73-21-16.