A B757 CREW DIVERTS TO AN ENROUTE AIRPORT AFTER THE ENGINE EPR; N1; N2 AND EGT CONTINUOUSLY HUNT IN FLIGHT INDICATING POSSIBLE FUEL CONTROL PROBLEM.

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THE LOG HISTORY OF THIS ACFT SHOWED A WRITE-UP FOR 'IN CRUISE L ENG EPR HUNTS; AS WELL AS N1 AND EGT; WITH N2 STABLE AND 85 FF.' THIS WAS SIGNED OFF BY MAINT. TKOF WAS BUSY WITH A FLAPS 15 DEG SETTING; MUCH TURB AND IFR CONDITIONS. THE FO RPTED THAT NO UNUSUAL FLUCTUATIONS WERE OBSERVED IN THE TKOF ROLL. AT CRUISE; WE OBSERVED THE SAME HUNTING CHARACTERISTICS AS PREVIOUSLY RPTED. NO OTHER SYMPTOMS WERE PRESENT; NO DUCT PRESSURE CHANGES; NO UNUSUAL SOUNDS; NO VIBRATION; ETC. AS THE FLT PROGRESSED; WE DISCUSSED THE SYMPTOMS AND CONSULTED OUR MANUALS. IT WAS THEN DECIDED TO TALK TO DISPATCH AS WELL AS MAINT. MAINT THOUGHT IT MIGHT BE A FUEL CONTROLLER PROB. WE TALKED TO DISPATCH ABOUT A POSSIBLE PRECAUTIONARY LNDG. AS TIME WENT ON; N2 INDICATIONS BEGAN TO SLIGHTLY HUNT ON THAT ENG; AND THE FUEL FLOW BEGAN TO GO UP. STILL NO OTHER SYMPTOMS; HOWEVER; WE DECIDED THAT A LNDG IN ZZZ WOULD BE THE BEST COURSE. A RERTE TO ZZZ WAS ARRANGED WITH DISPATCH AND ATC. WE DISCUSSED THE POSSIBILITY OF A PROB WITH THE ENG IN THE DSCNT AND TURNED ON IGNITERS AND THE APU. LNDG WAS UNEVENTFUL. WE WERE REDISPATCHED IN ANOTHER ACFT.