Hi, I have been having an issue with my seat leon pd140 bkd engine. The car seems like its not boosting properly. The car is straight piped from the turbo back. The issue i have is that the car seems like it is held back when driving it however if i drive the car hard for a while then it seems to cure the issue for a bit but usually comes back if drove normally. i have noticed that when there is less power i can hear a kind of turbine squeeling noise from the exhaust but when i hold the revs for a bit at constant speed the exhaust tone changes and the car picks up good speed. Thanks