I fill my juke up to 48 pounds worth and then when i drive it the trip metre shows 300 miles them when i drive half a mile it goes dowm by 1 mile then i drive another quarter of a mile and it goes down again ive only been driving half an hour and its down about 40 ? What the **** is going on ..it seems to be eating up more petrol then it should be .also the engine light comes on and when i play about with the fuel cap for a bit unscrewing and screwing it up again it goes off ?? Any ideas im lost ???