I am positive that the HCH-I will not run without fuel. Once, I was very low on gas in my 2004 HCH, and I stopped at a red light on an upward slope. Auto-stop kicked in, turning the engine off.

After the light turned green, I took my foot off the brake and to the gas, but the engine would not start back up. When I pushed the gas pedal to the floor, the ASST bar showed 100% (full), the engine was silent, and the car barely rolled forward (at half idle-speed) for 2 seconds. I pumped the gas pedal, and the engine eventually came back on, but I was careful to drive efficiently and to turn off Auto-stop (ECON off) until I reached the nearest gas station.

My guess is that the upward slope tilted the gas tank downwards, and the gas pump had trouble feeding enough fuel to the engine for it to start running again. All I know from that experience is that the puny 13-hp electric motor in the HCH-I was not designed and is not capable of propelling the car by itself without the ICE, and that I should not wait until the low-gas light turns on twice before heading to the gas station.