Not a simple answer as you would think. Depends on the year model. Although standard is 14.8 gal they also had a large size of 17.2 gal.
Now if your model is an early rear , say, 1981 then the size was 13.7gal.
The 2001 Toyota 4Runner has a fuel tank size of 18.5 gallons.
25 Gallons will fill the tank for a Toyota 4Runner
Inside the gas tank
Mounted on top and inside the fuel tank.
Most 1990 through 1995 Toyota automobiles were equipped with a 12 gallons fuel tank. The 12 gallons fuel tank is equal to 31 liters.
It sounds like you have a bad fuel sending unit. It is located in the fuel tank and the tank must be removed to replace it.
The gas tank on the 2010 Toyota 4Runner holds 24.0 gal..
The gas tank on the 2014 Toyota 4Runner holds 23.0 gal..
The gas tank on the 2009 Toyota 4Runner holds 23.0 gal..
The gas tank on the 2007 Toyota 4Runner holds 23.0 gal..
The gas tank on the 2002 Toyota 4Runner holds 18.5 gal..
The gas tank on the 2005 Toyota 4Runner holds 23.0 gal..
The gas tank on the 2008 Toyota 4Runner holds 23.0 gal..