when the car is first started there could be and normally is some white smoke in the cold but there should never be any BLUE smoke it will be very easy to see if its happening it WONT look like mist it should be a definate blue colour and it will kind of pump a lot more than just the white misty stuff(water in the exhaust system) when you rev it if its burning oil but it would have to be a serious amount to cause the problems you are describing but it could except really the excess petrol. The broken pipe, if it comes off the air filter towards the block and looks sort of ribbed like a vaccume cleaner pipe this does cause these problems, my friend had a split in his pipe near the jubalee clip that holds it on and it did pretty much what you are describing,but he wouldnt notice the fuel (too much money!) however as it was near the clip, a folded tea towel between the clip and pipe has proved a pretty good seal for now. These pipes are very important and to be absolutly sealed as they are supposed to be under pressure. I cant see them being that cheap to get hold of, those kind of moulded pipes usually aren't, breakers yard possibly or independant vw specialist, the one by me is pretty cheap, compared to dealer anyway!as long as I am thinking of the correct pipe as the mass air flow sensor is pretty new to me. Bring back the good old days, minimal electrics, no relays or sensors to confuse things, just air and fuel that mix then are compressed till they explode, how hard can it be!