On March 28, 1999, at 1515 mountain standard time, a Mooney M20K, N12HW, was substantially damaged during a forced landing following a loss of engine power while in cruise flight near Medicine Bow, Wyoming. The private pilot, the sole occupant aboard, was not injured. The aircraft was being operated by Blazie Marketing Service of Forest Hill, Maryland, under Title 14 CFR Part 91. The cross-country flight originated from the Salt Lake City International Airport, Salt Lake City, Utah, approximately 1315. A VFR flight plan had been filed; however, an IFR clearance had been activated 50 miles northwest of Medicine Bow for the flight to Omaha, Nebraska. Visual meteorological conditions prevailed at the accident site. According to the pilot, approximately an hour and a half after departing Salt Lake City, he began encountering instrument meteorological conditions. He requested an IFR clearance to climb to 23,000 feet mean sea level (msl). He received a clearance, and upon reaching his requested altitude, he leaned the engine's turbine inlet temperature (TIT) to 1600. The pilot stated that everything appeared normal for the first 5 to 10 minutes, then the TIT started rising. He applied full rich mixture, and the TIT came down. He requested and received a clearance to descend to 17,000 feet. The TIT continued to climb, and he requested another descent to 12,000 and continued to reduce power. At that time, the "engine started to run very rough, popping and spitting and not developing any power." He requested assistance from Denver Center (ARTCC) for vectors to the closest airport. At approximately 2,000 to 3,000 feet above the ground, he broke out of the clouds and located the Medicine Bow Airport. He observed a tractor positioned in the middle of the runway, and he selected a field 1/4 mile east of the airport on which to land. After a hard landing, the aircraft sustained damage to the right wing and the right landing gear. Two postaccident examinations of the engine were performed by FAA maintenance inspectors. Fuel was observed in the fuel tanks, engine, and the fuel injector nozzles. No fuel leaks were detected, and the oil quantity level was normal. The fuel flow divider appeared to be dry. No engine discrepancies were noted. Another engine examination was performed at Western Skyways in Montrose, Colorado. With the fuel boost pump on, the engine ran normally at ranges varying between 1,300 to 1,800 rmp. With the boost pump off, the engine began to surge at those rpm settings. The engine driven fuel pump was bench and flow tested and no discrepancies were found. The entire fuel system, including the fuel injectors and servo controller, was replaced with new parts, and the engine continued to surge. A replacement turbocharger was installed on the engine and test run. The engine continued to run rough and surge with the replacement turbocharger. Nothing was found during the investigation to determine what caused the loss of engine power.