Agreed. Basically ignore the fuel gauge and only go on L/100km - ie fill it up to the top of the tank, reset the trip-meter and drive around until the tank is showing near empty, then refill to the top again. Note the number of litres you put in the tank to refill it, then divide by the number of kms you travelled over that time period, then multiply by 100. Toyota fuel gauges are notoriously unreliable (in older cars) and non-linear (in some newer ones, especially 90s ones). Going off the gauge, my '97 Corolla will do 300km on the first half of a tank, ~100km on the next quarter, and then struggle to get more than 50km on the last quarter before the fuel light starts coming on.