PLT OF CPR SMT ACFT DEVIATED FROM ASSIGNED ALT AND TRACK WHILE HANDLING AN INFLT ENG MALFUNCTION.

Narrative

I WAS SITTING LEVEL AT 12000 MSL ON THE AUTOPLT JUST RUNNING IN THE TOPS OF A SHALLOW CLOUD LAYER WITH ABOUT 1/2 INCH OF MIXED ICE ON THE AIRFRAME FROM THE CLB THROUGH THE OVCST AT AKR WHEN THE L ENG BEGAN TO LOSE PWR AND SURGE VIOLENTLY BACK AND FORTH TO FULL PWR. OF COURSE I WAS SITTING THERE IN THE MIDDLE OF THE NIGHT AFTER A LONG DAY OF FLYING AND WAS REALLY CAUGHT BY SURPRISE. I UNHOOKED THE AUTOPLT AND THE ACFT WAS SEVERELY OUT OF TRIM AND I FRANKLY WAS OUT OF CTL FOR A PERIOD OF TIME TRYING TO GET THE AIRPLANE UNDER CTL AND ISOLATE THE PROBS. THE TIME I SPENT RECOVERING RESULTED IN MY CLBING TO AROUND 13200 FT AND I ADVISED THE CTR I HAD ENG PROBS AND WAS CLBING IN VFR CONDITIONS. SHE CAME BACK WITH TFC AT 12 O'CLOCK AND 3 MI AT 13000 MSL. I ACKNOWLEDGED SEEING THE TFC AND TURNED TO MY L OR SW TO BETTER AVOID THE TFC. I STILL HAD NOT SECURED THE VIOLENTLY SURGING ENG AND WAS TRYING TO TALK AND FLY AND THINK ALL AT THE SAME TIME. FINALLY; THE ENG QUIT SURGING AND RAN AWAY TO MAX TEMP AND MAX TORQUE AND SETTLED DOWN. I FINALLY SHUT THE ENG DOWN AND ASKED FOR SOME WX WITH VFR CONDITIONS AT CLOSE ARPTS. THE CLOSEST VFR WITHOUT THE 5000 FT OF OVCST AND ICE I HAD BEEN INCURRING ALL DAY WAS SBN; I ASKED FOR CLRNC TO SBN AND LATER WITHIN 90 MI SBN I CHANGED MY DEST TO MIE; WHICH WAS ABOUT THE SAME DISTANCE FROM MY PRESENT POS. WE LANDED AT MIE AROUND X00 PM LCL TIME WITHOUT FURTHER PROBS. LATER; WE FOUND THE FUEL CTL HAD MALFUNCTIONED CAUSING THE ENG TO RUN AWAY. I LEARNED A GOOD LESSON THAT MAYBE A LOT OF TURBINE PLTS ARE NOT REALLY EXPECTING IS THAT ALL ENG FAILURES DO NOT MEAN THE ENG STOPS BUT ALSO THEY CAN RUN AWAY. INTERESTING.