hi guys need some advice, the fuel pump in my calais has progressively been getting louder and now has a constant humming that is quite loud, also the car has now developed a surge, so to me these are tell tale signs its about die, so im gunna replace it, my question is, whats involved in replacing it? i know the tank has to be dropped, but im also wondering whether it will need recalibrating etc once im done, trying to avoid taking it to holden or anything like that, any help would be appreciated, cheers