Check the intercooler for possible leaks. If its leaking boost you will suffer power loss.
One tell tale sign of a leaking intercooler is oil deposits on the core of the cooler. If your not sure you can test it easily enough. Remove the cooler, seal up both ends to the cooler..and where the map, not maf, sensor is on the cooler if you removed it. Dunk it in water and pressurise the cooler using a bike pump and a football nozzle attachment. If you see bubbles. Its leaking.

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