SHORTLY AFTER TAKEOFF AFTER CLIMBING TO 900, THE FLT LEVELED OFF & THE PLT PULLED THE POWER BACK TO 24 INCHES MANIFOLD PRESSURE. SHORTLY THEREAFTER HE STATED THAT THE ENG BEGAN TO RUN ROUGH THEN QUIT. HE VERIFIED THE FUEL SELECTOR WAS POSITIONED TO THE RT FUEL TANK & THAT THE AUXILIARY FUEL BOOST PUMP WAS ON, CHECKED EACH MAGNETO, WITH NEGATIVE RESULTS. HE LANDED THE ACFT IN A FIELD GEAR UP. THE ENG WAS REMOVED FROM THE ACFT & PLACED ON A TEST STAND FOR THE ENG RUN. IT STARTED BUT DURING A MAGNETO CHECK AT 1,700 RPM, THE ENG BEGAN TO BACKFIRE MOMENTARILY WHEN POSITIONED TO THE RT MAGNETO POSITION, BUT CONTINUED TO RUN. THE MAGNETO ASSY WAS REMOVED & EXAMINED WHICH REVEALED NO DETERMINATION COULD BE MADE AS TO THE REASON FOR THE REPORTED TOTAL LOSS OF ENG POWER. THE FUEL SERVO WAS REMOVED AND PLACED ON A TEST STAND WHICH REVEALED THAT IT WAS NOT FUNCTIONING NORMALLY BUT COULD NOT BE DETERMINED IF THIS WAS POST OR PRE-IMPACT. AN AD HAD NOT BEEN ACCOMPLISHED. NO DETERMINATION COULD BE MADE AS TO THE REASON FOR THE REPORTED TOTAL LOSS OF ENG POWER.