Fuel (2003)

Young, very much in love, and expecting their first baby, the happily-married couple of Andrew and Cassie have all the reason in the world to be happy. However, as the two lovebirds drive down a tree-shaded serpentine road, all of a sudden, they run out of petrol. Alone in an unknown and seemingly isolated area, the next logical solution to their predicament is to search for a gas station, while the pregnant woman waits in the car--after all, there's not a soul in sight. Honestly, what could possibly go wrong?