On February 16, 2000, about 1000 Eastern Standard Time, a Piper PA-28R-200, N4531F, was substantially damaged during a forced landing in a field, after takeoff from the South Jersey Regional Airport (7MY), Mount Holly, New Jersey. The certificated private pilot was uninjured. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight conducted under 14 CFR Part 91. The pilot stated that the purpose of the flight was to practice maneuvers in the local area, in preparation for his commercial checkride. When he arrived at the airport, the pilot was informed that the accident airplane was undergoing maintenance and would be "momentarily down." The pilot observed no abnormalities during the preflight inspection or run-up check. He departed Runway 26, and at 50 feet above the ground, the engine made "backfiring and popping sounds," as it began to loose power. At 350 feet above the ground, the engine experienced a total power loss. The pilot reported that the engine was "not producing enough power to maintain lift." The pilot established an emergency glide, and prepared for a landing in a field. He extended the landing gear and added full flaps. The airplane touched down in the field, and during the landing rollout, the pilot observed a ditch in front of the airplane. He pulled back on the controls and added full power, "but got nothing." The airplane impacted the ditch, the left main landing gear was torn off, and the airplane slid about 500 feet before it came to rest. A witness reported that the airplane sounded like it was "missing and sputtering," after takeoff. According to the witness, the airplane attempted to turn around; however, it was losing altitude, and disappeared below the treeline. According to the mechanic apprentice who worked on the airplane before the accident, discrepancies had been reported with the manifold pressure gauge. On the day of the accident, he opened the cowling of the airplane and noticed that a 3/4" piece of copper tubing for the manifold pressure line was missing. This piece was found in the rubber manifold pressure line. The apprentice then reconnected the rubber tubing to the copper tubing. He stated that the manifold pressure line attaches to the #3 cylinder, and reported no abnormalities with that cylinder. He further stated that he did not observe the connecting bolts because he did not remove the bottom cowling to perform the procedure. The apprentice reported his work was overseen by a licensed mechanic; however, no entries were made in the engine or airframe logbooks for the maintenance that was performed. According to the licensed mechanic who approved the maintenance work, the apprentice removed only the top cowling, and did not remove any attaching hardware for the #3 cylinder, to perform the procedure. He visually inspected the engine after the maintenance was completed and noticed no abnormalities. A Federal Aviation Administration inspector, who examined the wreckage, reported that he opened the cowling and observed the #3 cylinder intake manifold tube was disconnected from the engine and lying in the cowling. The bottom portion of the tube appeared to be "flattened." The bolts and washers which connect the intake manifold tube to the cylinder were not found, as well as the "o-ring" which connects the tube to the manifold. The inspector observed "flakes," or metal shavings, in the induction box of the intake manifold. The "flakes" were consistent with the material of the intake manifold tube. The inspector reported the #3 exhaust manifold was broken at the muffler and appeared worn. Examination of the airframe and engine logbooks revealed that the accident engine received an overhaul inspection on February 20, 1991, and then was placed into "long-term storage." On August 4, 1999, the engine was disassembled, reassembled, and test run. The engine was installed on the accident airplane on September 20, 1999, at which time an annual inspection was also performed. No additional entries were made in either the airframe or the engine logbooks. At the time of the accident, the engine had flown 96 hours since major overhaul, and had accumulated 1,197 total flight hours.