Tried replacing the Fuel pressure regular but this was unsuccessful. Then tried a new iac controller - also unsuccessful, then I cleaned the MAF, also unsuccessful so this led me to check all the vac hoses by taking them off and making sure nothing had collapsed inside by poking something down them. Acting on intuition, I decided to see what the car ran like if I pulled the 22mm pipe off the plastic y pipe that carries the small vac tube to the inlet manifold . This links onto the crankcase emulsifier unit and happily for whatever reason the engine ran fine with this off. I also found that the pipe that comes across from the MAF/turbo pipework to the crankcase emulsifier had cracked half way along (its a plastic pipe with a foam insulation sleeve on it so you'd never know it had cracked). I mended this pipe, cleaned out the emulsifier unit with petrol first then 40 minutes in an ultrasonic bath at 50 degrees with some detergent and put it all back together again.

I dont really understand why the engine behaved like it did, it doesnt have a flame trap and I couldnt really feel a vac or a pressurisation of this pipe when I capped it with my finger. Ive read that flame traps sometimes give grief but mine doesnt have one being the turbo. Interested if anyone has any thoughts.

regards
pierso