One of the things I've learned about the 4Runner gas tank design is that it starts burping gas back through the vent pipe and shuts off the nozzle at a point where another gallon of gas will easily go in if you feed it slowly..

It seems to help if you turn the filler nozzle horizontal with the filler hose to the rear.

And on a trip out west where we were going into a really remote area and needed all the gas we could stuff in.. I learned that you can actually stuff more than a gallon in the tank (and extra 1/2 to 1 gallon.. e.g. 1 1/2 to 2 gallons total) if you feed it reallllll slow..