I broke down yesterday and its doing my head in!!! have a gurgle sound coming from my induction kit but not all the time it mainly happens when i try to rev the car and when the revs drop the car sounds like its going to die, coughing and spluttering. then clears and sounds fine untill i rev again, sometimes its fine when i rev. only gurgles on tick over. had recovery read falt codes and came up with po300 po301 po302 which are random engine,missfire cylinder 1 andmissfire cylinder 2. so we tested coil packs and they were fine injectors seemed fine and so were plugs. have noticed that my dump valve isnt dumping and cant hear wastegate anymore but that has been for around a couple of weeks now. also condensation seems to be present when engine warm,on a warm day. im lost!!!

 

This is probably over my head, but...your dump valve and wastegate may not be dumping because these misfires aren't allowing boost to build enough for it to be an issue.

I'm surprised you see no signs on the plugs...even if it's something else, I'd think you'd see some indicators. Which year/model do you have? It could be an air intake issue; something between the turbo and the intake, as you'd be getting underboost errors like I am if it was before the turbo. Feel around the intake pipe (carefully) when the engine is running and see if you can feel any leaks.

 

its a 2002 s3 225. had it at my workshop today and gave it a few revs.... then... gave it a few more..... suddenly the car started smoking in the engine bay and started sending clouds out of the exhaust!!! started to strip the intake system down and have it full of oil! so... I am now in the prosess of taking the turbo off it is full of oil. im now thinking the turbo seals have gone. found oil present in the intake system a few weeks and and took it to a garage they said it all seems fine... ummm dont think so! im wondering if it has been on the way out for a while??? havent had a lot of power for a while now. also why is there a water feed to the turbo? is there a oil feed to as not sure where the oil has come from???