What was found
ON ROTATION ECAM WARNING ACTIVATED AND NR 1 ENGINE EGT SPIKES TO OVER 900 DEG AND NR 1 ENG N2 SPIKES TO NEAR 119 PERCENT. RETURN FOR LANDING WITH NR 1 ENG AT IDLE. REMOVED AND REPLACED NR 1 EGT INDICATOR AND NR 1 N2 INDICATOR PER A310 MM 77-21-21-4 AND MM 77-12-21-4, AND PERF ENGINE IDLE AND HIGH POWER RUN PER A310 JRH, ALL PARAMETERS NORMAL. PROBLEM ON NR 1 EGT AND NR 1N2 INDICATION DUPLICATED ON GROUND. DURING MX ENG RUN PRIOR BOTH INDICATOR CHANGE.