I have a 2001 Audi A4 1.8T quattro with GIAC chip. I've been peaking at 4psi lower boost than normal. Already replaced 4 vacuum lines and zip-tied all the ends. Tried the DIY boost leak test (from the B5 A4 FAQ). Bought a new N75. I also tried pulling vacuum on wastgate and got nothing.

I just read that the wastegate is actuated by boost and not vacuum. Can I test the WG by applying air pressure from a small tire inflator compressor or trying to move the rod back and forth? How do I properly test the wastegate and also how do I know if it is bad or not?