Perhaps you can give it a try. Prepared yourself a mini tong of petrol. Then start measure the distance until the car actually started to "dry out", in this term the car engine will just goes dead. Then you can add the petrol into the petrol hole and start the car again. At that time you've already got the actual milage reading.

However, i heard it's not that good for the engine to run until petrol dried out. And it might take a while for the petrol to reach the engine after you refill the petrol manually. It's not a good experiment to perform but it is a good understanding/knowledge for yourself on the car you are driving daily. At least you'll know how far you can still drive if you missed a petrol station on the highway.

Haha... Yup. Not recommended but it's a good info gathering experiment. Perhaps one day if someone really that bad luck and met no petrol station until car engine failed, then only get the reading and post it here to let every one of us know..

I personally experienced before on an old car with fuel gauge and even the fuel warning light rosak. Tough experience but unable to get the reading since i don't even know when the warning light start to alert.