petrol warning light

Experienced the petrol warning light for the first time today - tbh I didn't realise it was there till then.
Just wondered if anyone has a rough estimate of how much is left. I mean, have I got 5 miles or 30 miles (presuming to be driving 'economically').
Also, the light was on only when stationary. When I started moving it went off and the petrol gauge went up - is this significant? I think I ruled out hills etc at the time.

5 miles on track and 40 at 50 on motorway. The light can be fickle though. It is only when it is on permanently that I start my 30 mile countdown.

Agreed bockers. The system seems to be sensitive to engine pressure as well as I find when getting below 1/4 of a tank the light will flash on when accelerating but goes back off with a light throttle. I never like to get too low anyway and the Coupe is remarkably efficient for a car with the performance. Its alot better than my Italians of old though - my old Beta HPE had a full tank when turning right and empty when going left!

I never worry about the light; just fill up after 360 miles whether it needs it or not

On my 16 I can get well over sixty miles with the light on, but Anita starts to get nervous if we're, say, on the motorway on the continent and starts making pointed comments.

Ok, I guess the consensus is there's no need to panic which is good to know.
It just seems to go down so quickly from quarter full to the line.

Yes this is true, it's the shape of the tank.

My only concern is, that given the age of our cars, we may start to pick up crap from the bottom of the tank with a low fuel level.

For this reason, I usually fill mine when the level gets to just below an eighth left and just before the light comes on. And I do have a spare fuel filter on the shelf in my garage should it need changing early prior to its regular change.

Yeah, good point possum. It's the first time I've hsd it so low, hence the question.
Regarding filter - I don't know if mine has ever been changed, what's the interval for a fuel filter?

I really don't see the logic here.

The crap is there no matter how full the tank is, just less concentrated if the tank is full. With a plastic tank, there aren't going to be rust flakes.

The fuel pick up is in the same place at the bottom of the tank all the time.

At least 40 miles in my vis using high octane fuel.