I still think there is a problem here, look at the pics to see what I mean..
This pic shows the S3 hose which one end (GREEN) pushes over the intercooler take off (RED 2nd pic) and is secured with a hose clamp. The other end (RED) has the hose connector on, with no o-ring, not that I can see anyways.. This end pushes into the turbo intake pipe on the driver side of the engine bay and is secured with a spring pin.
I still think that there is no o-ring on that connection which would cause a problem..
brilliant thread Im gonna stop quoting on forums
nice one jonnyc , although if this is the issue then how does that translate into lean mixture ? lost boost I would expect over rich ?
I can't really explain that, but I agree that it would be trying to over compensate with the fuelling, it is running silly pressures in the fuel system, this could well have something to do with it.. As to why its ending up lean I have no idea, it could infact be that its just getting pre ignition because its actually running stupidly rich for a moment. Over rich conditions can also cause pre ignition, especially in high compression engines..
I don't pretend to be an engine builder but it all kind of links up together, just throwing some ideas about..
I still think it would be worth having JKM check that connection on the IC hose..