Said It Still Had 30 Miles Left, But It Lied!
My 2005 1.6 litre Ford focus used let get up the low fuel warnings when it got down to indicating that there were 50miles remaining.
My journey in and out of work each day was only 3 or 4 miles each way, so when I got the warning early on one week maybe around Tuesday, I figured I could probably just keep using it all week and fill up at the weekend.
However probably on the Thursday or Friday the car indicated it still had 30 miles left, when I returned in the evening the car would not start. It had lied to me!
I had to walk to a nearby fuel station and buy a can and some fuel. I felt a bit cheated for some time. But thinking about it 30 miles worth of fuel probably only equated to around 3 the 4 litres and I used to park on a steep hill with the car pointing up hill, so I guess whatever was left when I parked it had all fallen back into the tank and was no longer enough to reach as far as the fuel pump.
So that was when I learned that it is probably best just to head for a fuel station as quick as reasonably possible as soon as the warning light comes on.