'02 7.3L, runs well, sudden loss of economy
'02 F250 Lariat Crew SB, 2wd , 7.3, 240K miles.
Daughter ran it out of fuel, after refueling and running the air out it seems to run well, but fuel economy is abruptly reduced by full 25%. The tank of fuel that was exhausted gave 17.7 mpg in combined city/hwy mileage. First subsequent partial (1/2) tank, all city/suburban driving gave me just 12.8 mpg. Second partial tank after fuel exhaustion incident gave me 18.1 mpg in all rural highway driving, at 58 mph.
I used to get 16.3 mpg city/suburban, now just 12.8 mpg.
I used to get 23.8 mpg highway, now just 18.1.
Computer diagnostics say fuel system is working well, and no trouble codes found. I can't detect any loss of power, nor is it emitting any smoke, except if I really hammer it, and even then it is very little, just as it has always done.
I haven't hooked it to my 7,000 lb camper to check for power loss while towing, but I will do so this weekend. (I historically have gotten 13.6-14.1 mpg pulling a 27' travel trailer with having two 500 lb motorcycles in the bed, down here in flat Florida)