What was found
DURING TAKE OFF, THE NR 1 ENGINE EPR GAUGES MATCH UP, BUT N1, EGT, N2, N3, FF WERE 30% LESS. THE AIRCRAFT CLIMBED OUT AND CONTINUED TO HAVE ASSY METRIC THRUST AND PASSED 10K FT ALTITUDE ENGINES CONTINUED TO RUN ABOUT 30 PERCENT APART WITH NOT MUCH THRUST TO CLIMB. AT THAT POINT, DECIDED TO RETURN TO BASE. INSPECTED THE NR 1 ENGINE P1 PROBE, AND FOUND DEBRIS CLOGGING THE PROBE INLET. REMOVED ALL DEBRIS AND INSPECTED P1 PROBE MM 73-21-04-6.