UK Car Repair: Corsa Fuel Problem Help!, fuel leaks, tyre pressures

Question
QUESTION: Hello, my P reg Corsa B has recently been using excessive amounts of fuel for no apparant reason...iv checked all pipes/hoses etc..all around the tank & carb...no noticable fuel leaks anywhere ...no strong smell of petrol....using around 3 times amount of petrol than should be...only started doing this for past week...used to put £5 in Monday & it lested until Thursday minimum now putting £5 in day & doing same journey only....please help  :(

ANSWER: Is here something restricting the drive such as ;  very low tyre pressures; a brake sticking on, etc. Or, is there an internal fuel leak?  Remove the dipstick  to check the engine oil and smell it, perhaps it is overfueling and the excess is seeping down into the sump.  If so, don't drive the vehicle until you find the cause and have changed the contaminated fuel.

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QUESTION: thanks for the theory but there are no restrictions preventing it from normal operation...this has only just started doing this in the last week...with the theorys you mentioned it would be obvious there was something at fault...but like my question says we cant understand why the massive fuel consumption when there is no obvious visable fault.

Answer
Sometimes it is the obvious we fail to see! Did you check the engine oil?  Clearly the fuel is being lost at an exagerated rate.  It is either burning it, or it is leaking somewhere. Such excessive burning would likely show in dark exhaust smoke and eventual fouling of the plugs.  Leaks can be internal into the engine or external. There aren't any other options!