hi all ive got a mk1 1.6 focus that has a fueling problem,when theres less then 1/4 tank ov fuel its brearks down but if i get out and undo the petrol cap and get back in its ok its been an ongoing problem for the last year,its been to ford 4 times and they cant find the problem,ive changed the fuel filter 6 times and still its playing up has ne1 come across this with their focus its also had superchip bleu fin and the bloody thing is doing about 40 miles to 20 bucks petrol....grrrr