On August 18, 2010, about 1000 central daylight time, a Cessna 182T, N1142U, received substantial damage on impact with terrain during a forced landing on a field near Mosby, Missouri. The pilot reported that the airplane engine experienced a loss of power to idle power during climb. Visual meteorological conditions prevailed at the time of the accident. The 14 Code of Federal Regulations Part 91 personal flight was operating on an instrument rules flight plan. The pilot and passenger was uninjured. The flight originated from Kansas City International Airport (MCI), Kansas City, Missouri, about 0940 and was en route to Dubuque Regional Airport, Dubuque, Iowa. The pilot stated that he flew the airplane once on a "small trip" after an annual inspection without incident. The second flight since the inspection on the day before the accident was to be from DBQ to MCI to DBQ. The second flight on the day before the accident and flew from DBQ to MCI on an instrument rules flight plan with a filed altitude of 8,000 feet mean sea level (msl). During the second flight, the manifold pressure was "probably" 26 inches and the engine speed would have been in the upper green. He also said that everything was "normal" and in the "green." He said that he sets a climb fuel flow of 15.5 gallons per hour (gph) and leans the fuel flow to about 13 gph after the airplane levels off. About 10-15 minutes after departure from DBQ and at altitude of 8,000 msl, the engine "sputtered" for approximately 5 seconds as if the fuel was "cut-off" and the engine then regained power and operated normally. By the time he turned off the autopilot and established an airspeed of 70 knots, the engine regained power. He was at 8,000 feet for a "few" minutes and the fuel flow was 13 gph, the manifold pressure was about 26 inches, and the engine speed would have been in the upper green, "1,500" revolutions per minute (rpm). He was about 5 nautical miles (nm) from the Monticello Regional Airport (MXO), Monticello, Iowa, at the time of the power loss and decided to divert to that airport where the airplane landed without further incident. It was the first time that he experienced the airplane engine "sputter" since he owned it. He never experienced water contamination in the fuel system. After landing, he taxied to the ramp and performed several run-ups during which he checked the magnetos. The run-ups and magneto checks were reported as "fine." He asked several mechanics at MXO to look at the airplane. They reportedly asked the pilot if he had obtained fuel from a fuel truck to which he responded that he had done so before he departed. The pilot said the he normally had the airplane fueled before it is placed in its hangar but on this trip it had not been. He and the mechanics checked the fuel sumps for contamination and none was noted. They also did a visual inspection of the engine and did not see any anomalies. He started that airplane and performed a run-up. He then performed two take-off and landings and there were no problems with the airplane or engine. The pilot stated that he preflighted the airplane and checked every fuel sump and did not find any water contamination. He filed for 9,000 feet mean sea level (msl) for the return flight from MCI with an initial clearance altitude of 4,000 feet msl. Everything was normal with the takeoff and climb. He climbed with a fuel flow of about 15.5 gallons per hour and a maximum power setting, which he thought was 26 inches of manifold pressure. He was at 4,000 feet msl for 7-8 minutes. After about 10 minutes, he received a clearance to direct to DBQ and a climb to 9,000 feet msl. About 15 minutes after departure and while climbing through 5,200 feet msl, the engine "sputtered" and went to idle. The engine regained power after about 5 seconds but then was "quickly" lost and was not regained. The engine speed was about 600 revolutions per minute (rpm) and it seemed like the engine was "starving" for fuel. He moved the throttle and mixture controls inward and outward and turned on the electric fuel pump. The engine still did not regain power. He established an airspeed of 70 knots, he notified Kansas City Departure telling them he had an engine problem. The engine speed initially improved while he talked to Kansas City Departure. He decided to attempt a landing at Midwest National Air Center Airport (GPH), Mosby, Missouri, which was about 5 nm away. While flying to GPH, the engine continued to operate with an engine speed of 600-650 rpm. He suspected that the engine was not receiving enough fuel and he tried several ways to increase fuel flow such as adjusting the throttle and mixture in and out several times as well as turning the electric fuel pump on. About 2 nm from GPH, the pilot realized that he would not be able to reach GPH so he performed a forced landing on a grassy, rough, and down sloping pasture lined with trees. During the forced landing, the airplane struck a ditch and collapsed the front landing gear. An examination of the airplane by the Federal Aviation Administration revealed that the air intake/filter and exhaust system were unobstructed. The fuel vent system, fuel sumps, and fuel strainers were unobstructed. Fuel was noted throughout the fuel system. Rotation of the propeller by hand confirmed compression of all cylinders, valve train continuity, and continuity to accessory section. Control continuity of the throttle, propeller, and mixture controls was confirmed. Both magnetos produced a spark through each lead when rotated by hand. The fuel servo, RSA-5AD1, part number 256544-3, serial number 70842810, and flow divider part number 2576564-1, serial number 023346, and engine-driven fuel pump, part number LW-15473, date code 0405, were removed for further testing and examination. Flow bench test results of the fuel servo were reported as within current serviceable limits and no internal leakage was observed. The fuel inlet screen was unobstructed. The fuel and air diaphragms were intact and pliable. The fuel diaphragm contained a blue colored tacky residue over an estimated 40 degree sector consistent in color with 100 low lead aviation fuel residue. The flow divider was also tested and no obstructed flow was noted and the internal diaphragm did not stick and was pliable. The flow divider outlet fitting threads that fit into the divider body were wrapped with a white tape consistent in color and thickness of Teflon tape. One of the four fuel servo impact tubes contained a similar blue residue. The National Transportation Safety Board Investigator-In-Charge actuated the fuel pump by hand and no anomalies that would have precluded normal operation were noted.