On June 10, 1996, at approximately 1800 mountain daylight time, a Piper PA-28-150, N5172W, sustained substantial damage when it landed short of Bountiful Skypark runway 34, Bountiful, Utah, following a loss of engine power. The aircraft was operated under 14 CFR 91 and the student pilot, the sole person on board, received minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the local flight, which originated at Bountiful Skypark. The pilot stated that during his preflight inspection, there were "over 20 gallons" of automotive fuel in the aircraft's left tank and 5.5 gallons in the right tank. A copy of an entry in the aircraft's engine logbook indicated the aircraft was modified in accordance with an FAA Supplemental Type Certificate (STC) to operate on automotive gasoline on September 20, 1995. In a written statement to an FAA aviation safety inspector dated June 16, 1996, he stated that upon entering the aircraft, the aircraft's fuel selector valve was in "right tank" from its previous flight, but "I believe I recall switching to the left tank", although he was not certain of this. The pilot stated that "the power sagged" immediately after liftoff, while in ground effect, but that it "restored immediately" when he positioned the mixture control to full rich. He stated that he then continued the climbout because "it appeared too late to abort" (NOTE: Skypark runway 34 is 4,700 feet long.) He reported that he "experienced a few short lived power sags before my downwind turn" and did not attain pattern altitude at the usual point in the traffic pattern (which is right-hand for runway 34.) He stated that on downwind, "there were more power fluctuations [and more] altitude was lost but the speed was maintained at 80 mph. The mixture control seemed ineffectual and I could not find a throttle setting that would improve the performance." He went on to report: "I mistakenly employed 10 [degrees] flaps [as I] entered the base turn. The engine was then surging between 1500 and 2000 rpm....as I turned to final the engine quit running." The aircraft landed about 300 yards short of runway 34 and struck a ditch. Witnesses observed fuel leaking from the aircraft after the accident. The pilot stated that another individual, who responded to the scene to provide assistance, "turned the fuel Selector Switch to a neutral position", a position he described in a phone interview with the NTSB investigator-in-charge (IIC) on June 26, 1996, as halfway between the left tank and right tank positions. This individual was subsequently located and, in a telephone interview with the NTSB IIC on January 13, 1997, stated that at the accident scene, he switched the fuel selector valve from a position which he described as "clockwise to the right" to "OFF." The pilot stated during the June 26 phone interview that he did not recall attempting to switch fuel tanks during the inflight engine problems. The FAA investigator assigned to the accident reported finding two tablespoons of automotive gasoline in the accident aircraft's carburetor float bowl. Witnesses who saw the airplane reported to NTSB officials that they heard the airplane making "popping" noises, or "running really, really poorly and...backfiring" prior to the accident. The FAA investigator subsequently reported, on June 24, 1996, that the engine had been run sucessfully in a test run. According to the pilot, the engine, a Lycoming O-320-A2B, had 1,370.25 flight hours since its last overhaul, and 65.61 flight hours since its last inspection. Copies of maintenance records supplied by the pilot indicated that the most recent annual inspection, on June 26, 1995, had been signed off as follows: "I certify that this aircraft has been [inspected] IAW an annual inspection and a list of [discrepancies] has been provided to the owner." Completion of a 100-hour inspection was also documented on that date. The most recent annual inspection entry on which the aircraft had been signed off as airworthy was dated September 6, 1993. No other evidence was furnished to indicate that the aircraft had been signed off as airworthy, per annual inspection, within the 12 calendar months preceding the accident.