well, consumption is set in the magic data.
If you're driving a custom track without the custom magic data, it will use the original one which can be good , or not.
Running out of fuel is one consequence, but also grip, AI , bumps etc,etc...
Use the custom magic data if there is one, thats my advice.
more info here from Rob [
gadareth.altervista.org]
btw : Sometimes it may be helpfull to name the track