vaccume leak

[Poodles]

More than likely it's a boost leak, in other words a leak anywhere after the turbo. That's a lot of pipes, and a lot to check, but it's not too hard to find. You can make a PVC pipe with a cap on it that will fit in the intake so you cna pressurize the system with the car off and listen for leaks. If you can hear it but can't find em, use the old trick they use on tires, soapy water sprayed in the general area with bubble up with the leak.

If it's not this...if could be leaky injectors, but the pipes on the intercooler, ect go out sooner, so it's a safe bet that's where the problem is...