SR22 PLT DECLARES AN EMER DUE TO ENG PARTIAL PWR LOSS AND MAKES A PRECAUTIONARY LNDG.

Narrative

I DID A THOROUGH PREFLT BEFORE LEAVING ZZZ ON AN IFR FLT. ALL ENG INDICATIONS WERE NORMAL FOR THE FIRST 25 MINS OF THE FLT; BUT THEN; WHILE CLBING THROUGH 15000 FT (I WAS FILED FOR 17000 FT); IT STARTED SPUTTERING AS IF IT WAS NOT GETTING FUEL. THE REASON I SAW THIS IS BECAUSE THE ENG WAS NOT RUNNING 'ROUGH;' IT JUST WENT INTO A COAST MODE ONLY OCCASIONALLY (EVERY 30 SECONDS OR SO) TRYING TO COME BACK TO LIFE. I SET UP FOR BEST GLIDE WHICH WAS NOT FAR BELOW BEST RATE OF CLB SPD AND ADVISED ATC THAT I HAD LOST PWR; WHILE SIMULTANEOUSLY WORKING THROUGH THE EMER CHKLIST. CTR ASKED MY INTENTIONS AND I TOLD THEM I WANTED TO DIVERT TO ZZZ. CTR THEN ASKED IF I COULD MAINTAIN 14000 FT. I REPLIED NEGATIVE AS I WAS ALREADY DSNDING THROUGH THAT ALT WITHOUT PWR. CTR ASKED ME IF I COULD HOLD ANOTHER SLIGHTLY LOWER ALT (CAN'T REMEMBER EXACTLY WHAT) AND I AGAIN REPLIED NEGATIVE AS I WAS STILL WITHOUT PWR. AT THAT POINT I DECIDED TO DECLARE AN EMER TO UNEQUIVOCALLY LET CTR KNOW THAT I NEEDED PRIORITY HANDLING AND THAT I WOULD BE CIRCLING DOWN TO A LNDG. CTR WAS HELPFUL AND FRIENDLY AND AS I DSNDED THROUGH 10000 FT; THEY HANDED ME OFF TO APCH. APCH ASKED IF I HAD ZZZ IN SIGHT. I TOLD THEM YES; AND THAT I WAS CANCELING IFR AND WOULD LET THEM KNOW BY PHONE THAT I WAS OK ONCE I LANDED. DSNDING THROUGH 9000 FT; THE ENG CAME BACK TO LIFE AS SUDDENLY AS IT QUIT. I MADE A PRECAUTIONARY LNDG ZZZ AND TRIED TO TROUBLESHOOT THE PROB. AFTER DISCUSSION WITH MECHS; AND WITH THEM NOT BEING ABLE TO FIND ANY PROBS; IT WAS DECIDED THAT I MAY HAVE EXPERIENCED VAPOR LOCK. DURING THE CLB; I HAD TURNED OFF THE FUEL PUMP CLBING THROUGH ABOUT 8000 FT. FROM NOW ON; I AM GOING TO LEAVE THE FUEL PUMP ON DURING THE ENTIRE CLB AND FOR THE INITIAL 10 MINS OF CRUISE FLT TO MINIMIZE THE CHANCE OF A REOCCURRENCE.