Movie where the generator is almost out of gas and cannot be allowed to go out.

This was a horror movie, I’m guessing late eighties or early nineties. It had a Stephen King vibe, but I haven’t found it in his catalog. All I remember is that the protagonists were in a cabin in the woods, which had a string of electric light bulbs powered by a gas generator. There was something in the woods that was stalking them, but it was repelled by light. As long as the lights stayed on, they had a fighting chance, but if the lights went out, it would get them. I don’t remember what “it” was, aliens, demons, criminals, insects…simply can’t remember. They were nearly out of gasoline, and the generator was sputtering, causing the lights to flicker.