CORP ACFT MAKES PRECAUTIONARY LNDG DUE TO QUESTIONABLE FUEL REMAINING.

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I WAS THE FO. THE LAST RPTED FUEL AMOUNT; AS RPTED BY THE LAST CAPT THAT HAD FLOWN THAT ACFT; WAS SHOWN IN THE FLT MAINT LOG AS 65 GALLONS. CAPT PUT IN A FUEL ORDER OF 10 GALLONS; WHICH WOULD BRING UP THE TOTAL FUEL ON BOARD TO 75 GALLONS. WE KNEW THAT THE FLT WAS SCHEDULED FOR EXACTLY 1 HR; THE WX WAS RPTED AS VFR FOR OUR ENTIRE RTE OF FLT; THE AIRPLANE BURNS 40 GALLONS PER HR; WE PLANNED ON BURNING 40 GALLONS TO ARRIVE AT OUR DEST. WE NEEDED 30 GALLONS MORE FOR LEGAL IFR RESERVES; THAT LEFT US WITH 5 GALLONS OF EXTRA RESERVE. THAT AMOUNT OF FUEL WAS ENOUGH TO LEGALLY AND SAFELY COMPLETE THE TRIP. WE DECIDED TO SWITCH THE TANKS TO THE AUX'S AFTER LEVEL OFF. WE WANTED TO BURN THE AUX TANKS DOWN TO 1/8 TANK; AS PER COMPANY SOP. CAPT HAD STARTED THE TIMER AFTER I SWITCHED THE TANKS. WITH THE TANKS AT 1/4 AND AT OUR PRESENT BURN RATE THERE SHOULD HAVE BEEN 28 MINS OF FUEL. 7 MINS AFTER SWITCHING TANKS THE R ENG BEGAN TO SURGE AND THE 'R FUEL BOOST PUMP FAIL' ANNUNCIATOR CAME ON. WE BOTH IMMEDIATELY SUSPECTED A FUEL PROB. I SWITCHED THE R ENG BACK TO THE INBOARD TANK AND THE ENG SURGE WENT AWAY. AT THIS TIME WE FELT THAT OUR RESERVE FUEL LOAD MAY HAVE BEEN COMPROMISED AND DECIDED TO MAKE A PRECAUTIONARY STOP FOR FUEL IN TOLEDO. WE PUT ON A KNOWN AMOUNT OF FUEL AND FINISHED THE TRIP WITHOUT FURTHER INCIDENT.