Narrative:

During cruise at 3500 ft a gradual loss of fuel pressure was noticed. Use of the boost pump and trying other fuel tanks did not correct problem. Left main had been used for approximately 30 mins. Right tank and both auxiliary tanks were full. Engine continued to run but was unable to hold altitude. ZZZ airport was approximately 6 NM to the east; but a frontage road was about 1 NM away and was a safer alternative. I then made a mayday call on the local CTAF frequency stating my location; identify; and intentions to land on the frontage road. Having some time; I retried switching tanks and boost pump with no increase in fuel pressure. I then prepared for landing and checked the road for any traffic or obstructions. After landing and securing the aircraft; the fuel tanks were checked and found to contain the expected levels of fuel; all full except the left which was approximately 3 inches below full. A blockage of the fuel system somewhere past the selector valve is suspected.

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Original NASA ASRS Text

Title: BE35 MAKES FORCED LNDG ON ROAD WHEN FUEL PRESSURE FALLS BELOW THAT NECESSARY TO MAINTAIN ENOUGH POWER TO REACH THE NEAREST ARPT.

Narrative: DURING CRUISE AT 3500 FT A GRADUAL LOSS OF FUEL PRESSURE WAS NOTICED. USE OF THE BOOST PUMP AND TRYING OTHER FUEL TANKS DID NOT CORRECT PROB. L MAIN HAD BEEN USED FOR APPROX 30 MINS. R TANK AND BOTH AUX TANKS WERE FULL. ENG CONTINUED TO RUN BUT WAS UNABLE TO HOLD ALT. ZZZ ARPT WAS APPROX 6 NM TO THE E; BUT A FRONTAGE ROAD WAS ABOUT 1 NM AWAY AND WAS A SAFER ALTERNATIVE. I THEN MADE A MAYDAY CALL ON THE LCL CTAF FREQ STATING MY LOCATION; IDENT; AND INTENTIONS TO LAND ON THE FRONTAGE ROAD. HAVING SOME TIME; I RETRIED SWITCHING TANKS AND BOOST PUMP WITH NO INCREASE IN FUEL PRESSURE. I THEN PREPARED FOR LNDG AND CHKED THE ROAD FOR ANY TFC OR OBSTRUCTIONS. AFTER LNDG AND SECURING THE ACFT; THE FUEL TANKS WERE CHKED AND FOUND TO CONTAIN THE EXPECTED LEVELS OF FUEL; ALL FULL EXCEPT THE L WHICH WAS APPROX 3 INCHES BELOW FULL. A BLOCKAGE OF THE FUEL SYS SOMEWHERE PAST THE SELECTOR VALVE IS SUSPECTED.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.