On-board computer

How reliable is the range on the computer? I left my house earlier and it had 28 miles to go, drove a mile down the road and the petrol light came on, the needle on the fuel gauge was half in the red. Then i looked again on the way home how many miles i had to go and it was blank? (just - ---)

Cheers Shaun
 
on monday coming back of hols my petrol light came on.
did 32 miles to motor way-services to get some fuel registerd 0
on the gauge.was brickin it as it said 35 left in tank.
 
on monday coming back of hols my petrol light came on.
did 32 miles to motor way-services to get some fuel registerd 0
on the gauge.was brickin it as it said 35 left in tank.

lol ok cheers for the reply. i guess its not reliable at all then.
 
i think the tank only has 30 miles on the red but the comp aint v.reliable i get the topup oil come on at start up sometimes and then it will go back to normal after driving and on checking oil levels found them to be efficient