THE PLT RPTD THAT HE WAS CRUISING AT 9,000 FT WHEN HE OBSERVED THE EGT GAUGE INDICATION DROPPING. THE ENGINE BEGAN TO RUN ROUGH AND HE NOTICED A FUEL ODOR IN THE CABIN. THE CARB AIR TEMP GAUGE WAS INDICATING 'WELL OUT OF' THE ICING RANGE. HE SELECTED CARB HEAT, BUT THE ENGINE DID NOT RESPOND. HE THEN SHUT THE CARB HEAT OFF. THE ENGINE EVENTUALLY LOST PWR ALTOGETHER. ATC PROVIDED RADAR VECTORS TO A NEARBY ARPT BUT THE ACFT CRASHED INTO TREES ABOUT 1 MI FROM THE ARPT. POST-CRASH EXAM OF THE ACFT REVEALED NO EVIDENCE OF ANY PRE-EXISTING MECH FAILURE/MALFUNCTION. TWO SPARK PLUGS WERE REMOVED AND FOUND TO BE WET W/FUEL. DURING A SUBSEQUENT TEST-RUN, THE ENGINE DEVELOPED FULL PWR. THE PLT HAD BEEN REPEATEDLY ADVISED OF ICING CONDITIONS IN CLOUDS AND PRECIP ALONG HIS ROUTE OF FLT DURING PRE-FLT & IN-FLT WX BRIEFINGS. A FEW MINUTES BEFORE THE PWR LOSS, HE RPTD TO A FSS THAT HE WAS IN 'HEAVY SNOW'. HE WAS NOT IFR RATED. 16 HRS OF HIS LOGGED ACTUAL INST TIME WERE LISTED AS PIC.