Rover owners: MG ZS+ TD 2003 confused

Hi everyone, just wondering if you can help just purchased the mg, and it has a problem starting then after it warms up it puffs smoke and loses power when it does this the car dips as though it's ran out of fuel or something, checked the boost Pipe, fine turbo is definitely going to need replacing but when hooked up to the diognostics the one thing that keeps coming up is a maf sensor fault has anyone had this or these issues before and is it a common fault, if anyone can help would be greatly appreciated just can't wait to get out on the road and take her for a spin

thanx