I remember reading this sometime late 80's early 90's. I'm almost certain it was a short story. I read it in English, in Ireland, but it was almost certainly an American author. It could have been written any time from the 50's to the 80's.
Two guys — some kind of engineers — are in one of their garages, drinking, one of them has an idea, and using parts he has lying around, creates an inertia-winder.
It creates a bubble of inertia-less space, but because the guys are well into their cups, they didn't limit the bubble and it keeps increasing in size, and they can't turn it off.
Havoc ensues as cars accelerate rapidly, brakes don't work, people launch themselves into the air as they stand up, lots of fun and frolics.
Eventually it's put on top of a rocket and basted off into space to, the world returns to normal.
The guys then figure out how to limit the effects and build predictable inertia-winders. They're tasked with going and finding the original and switching it off before it destroys the universe.
They create a spaceship out of an old car, with oxygen creating moss/lichen growing under the hood of the car which they can use for food. Just before they find the original inertia-winder the moss/lichen "evolves/wakes/mutates" and starts to attack them.
They find the original winder and find aliens playing in its bubble. The aliens love it and tell they guys they've stopped it expanding but they're keeping it as a play ground.
The aliens could have been mythical creatures.
The guys then return home.