hi im not sure as mine had other faults as well at the time but it could be the imrc on its way out as if it does go i think the light will stay lit . get your car warm look for the silver box thats bolted onto the bulkhead follow the cable that comes out of it you should see it connected onto the inlet manifold rev the car past 4000rpm and you should see the imrc open then close it could also be the cables snapped so worth a look pal
.. as for the fuel i put fuel in by the litre so i get 10 litres most people dont so they put £10 in and get 8.75 litres etc so its less than £10 worth of fuel in theory lol i only do this as the price changes from garage to garage so much
cheers mark