Q: Loss of power in 1st gear

Hi there. Adjusting turbo boost for this engine is a compromise at best. Setting boost to be optimal for 3rd, 4th and 5th gear (without over-boosting) means 1st and 2nd gear don’t get that much boost. Stepping up boost for 1st and 2nd means you are likely over-boosting in the higher gears. Adding after-market boost control buys you additional performance control, but there is still just too little time spent in 1st gear to spool up the turbo in a useful manner. If you have lost boost in ALL gears, that is a different issue; and an examination of the turbocharger, blow-off valve, and control gear is in order. If so, I would recommend having a loss of power inspection completed by a mobile, professional mechanic, such as one from YourMechanic, so that the correct repair can be made.