This is most likely due to unmetered air entering the cylinders. There a few things for you to check
- #1 Always. Check for Boost Leaks In case you forgot how : https://www.youtube.com/watch?v=fdjadhUP1u4
- If you can not find the leak, use a smoke tester.
- Ensure throttle plate is not stuck and is not bent.
- Check the trottle cable to ensure it is not stuck or too tight.
- What is the TPS volt value at idle position? (Aim for 0.63)
- Blocked off your FIAV? That can cause an internal leak that bypasses the throttle body.
- Biss screw set properly?