If you have a gasoline engine in a car, put some fuel in, and then swap to a diesel engine, the game crashes.

I also noticed that if you fuel a car with lava, then remove lava from the accepted fuels list in the config, the game crashes.

I would suggest making it so if a vehicle's tank has the wrong fuel, it just gets emptied.

Yup. That's a problem. Same issue happens if the default fueling factor is set to a fuel that doesn't exist. Will have to tweak both to prevent this issue.

Fixed in V17.2.0.