When the ignition is turned on the petrol pump in the tank runs for about 5 secs...I turn off the ignition without starting and leave for 2 mins....then i turn on the ignition again and the pump runs for another 5 secs ....when i do start the engine it does it half-heartedly and just catches then i can rev it slightly everything then is ok except for this uneven idle when hot only....when cold the engine idles lovely as i suppose it`s on the enrichement setting until warm or hot then this bad idle takes over....you can actually watch it warm up and see it happening......any ideas??.........

By the way my friends S40 GDI 1.8 engine ...when you turn the ignition on you don`t hear anything not even a pump going and when you start it, the engine seems to start before the key is turned ...it immediately revs up