This happened twice as i was entering the freeway, one thing to consider is that the incline to actually get to the entrance is a very very steep 1/2 block when you turn onto the road. Because the road that leads up to it the elevation changes quick. Anyways i believed i may have ran or was running out of gas but my gause read just under 1/2 tank. And i havent traveled enough miles to empty it. The engine surged as i gently pressed on the pedal to increase my speed. It was 99° outside as well. I made it to a gas station filled up and it waited again to freak me put the same way when my gauge was 1/2 tank full. Dang im confused what this car possibly want. Bad gas? Clogged fuel line? Battery has been replaced. Reminds me of a vapor lock engine. Help help!! Posted via the PriusChat mobile app.