Yeah, the mileage on the car isn't so important--I wonder if the car sat with less than a full tank of gas, though. If there was any moisture in the tank, that caused your problem. The float-type device which registers the fuel level can "stick", thereby causing the guage to stop reading 'Full'. If any corrosion formed on the float arm, it's getting stuck at the 3/4 level even though the fuel is higher than that.
Given what a huge PITA it is to work on the sending unit/fuel pump assembly in the tank (on which the float is located), I'd just grin and bear it. As long as you
know that the tank is full, and as long as the guage is reading correctly at lower levels, you're okay.
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1990 5spd V6 Camry (Still kicking at 393,000km) 1991 Celica GTS -- Pappa needs a 3SGTE...and AWD for all this friggin' snow
Honda my A$$, you just can't kill a Yota...