It will take off really fast in first second and third. Builds plenty of boost. In fourth if I hold it to the floor it pulls good once it hits 20 pounds boost, tops out at 22 pounds, then drops down. I think the surging is the computer cutting it back so it doesn’t blow up. I do have access to a VCDS. But not sure what to look at, or where things should be running. Had the intake off when motor was installed, no blockage. Adjusted the rod on the vacuum pot,On the turbo. Used a vacuum pump, and set clearance between stop and arm,With a feeler gauge, at a specific vacuum.per a post I had read. Don’t remember the exact procedure at the moment. No anti-shutter valve, no EGR. Did install new timing belt kit with water pump. Used cam tool, crank tool, And pin in injector pump. Don’t remember what injection pump timing is at, set it with a snap scanner. That is about the only procedure the snap on scanner will do to a Volkswagen, at least mine.