I had the exact same problem on my 07 STi - Is the car idling rough?? go and have a look under the bonnet and see if there's a small hose on top of the engine itself, at the front, which has come off. It's about 3-5mm in diameter and it connects to a 90 degree metal pipe.. I know this sounds vague..PM me and I can help you more if you wish. I think they pop off under full boost. Do you have mods??
You will need to go to a garage to get the CEL cleared.
Cheers
Zombee
