I for one, can attest to the fact that in a prolonged dive the engine will run dry.

Here I am right, having a good time flying the good ol' trainer and decide to climb up real high and go into a dive straight down. No problem, I thought, I'll pull out real slow so as to not rip the wings off. So now I'm pulling out of the dive, leveling out at about 20 feet or so and figure I've got just enough speed left to do a tight loop. Right about at the top of the loop, the engine went dry and sputtered. The landing gear actually brushed the tall grass exiting the loop. Just about had to check my shorts on that one.

I vowed to never pull that stunt again. It didn't last long though, tried it again and this time hit one little pine tree in the middle of the field. The plane lived though...

So yeah, the engine will die after a while.