Ok bud.
To start with, check the hose that attaches to the MAF to turbo pipe. Undo the retaining clip, and pull it off to see if there is oil residue on the inside. If there is, remove the MAF to turbo pipe and clean out with petrol or paraffin.
Also remove the breather pipe (I think it comes from the rocker cover) and clean that out with petrol or paraffin clean the pipe that comes out of teh rocker cover too. You'll probably only be able to do this, with some paper rag etc...
Next, remove the black metal box on the front of the engine (this has 1 pipe going towards the sump and one, to the back of the rocker cover). Wash this out with petrol/paraffin too, preferably from the top pipe, through to the bottom pipe. This should have the most gunk/oil come out of it as, it's the oil separator.
At the back of the rocker cover, on the drivers side, you'll see the PCV (looks like abolt with a hose attached). This will plumb into pipes around the throttle bodies.
You can check this PCV for and make sure it's still working. It should be a one way valve so, will only let gas out of the rocker cover, and not back in.
Again, take off all the associated pipes and clean with petrol or paraffin.
Stick it all back on and see how she runs.
Ideally what you'd do is rip all that stuff out, invest in an aftermarket catch tank, and vent it to atmosphere, instead of back into the intake system. Remove the PCV and block off with a 3/8 BSP cap and loop the pipes by the throttle bodies together. There is a thread around with info on how to do this.
