Rite guys my focus has developed a running fault.

The car will tickover fine but when you try rev the car nothing happens at first it hesitates then will rev up,same when driving if you come off the throttle then back on nowt happens at first then it will splutter and pop and bang?? Its also quite bad when you corner or come round a round about then try to accelerate, its as if its running out of fuel so was wondering if my pump could be on its way out or anybody have any other ideas?

Cheers