What was found
DURING CRUISE FLIGHT AT 10,000 FEET THE LT ENG MANIFOLD PRESS STARTED TO FLUCTUATE & DECREASE. WITHIN THREE TO FIVE MINUTES MANIFOLD PRESS DECREASED TO NINETEEN INCHES WHICH WAS ATMOSPHERIC PRESS WITH LT THROTTLE FULL FWD. OIL TEMP BEGAN TO RISE TOWARDS UPPER RED ARC, 240 DEGREES, AT THAT TIME PILOT DECIDED TO SHUTDOWN LT ENG & DECLARED AN EMER. DIVERTED & LANDED WITHOUT FURTHER INCIDENT. INSPECTION OF ENG REVEALED METAL PARTICLES IN OIL FILTER. R & R LT ENG. ALL OPERATIONAL CHECKS OF ENG WERE NORMAL.