Boost issue

[Cellec]

I have an 07 GTI fsi I was having a couple codes and one was p000A I replaced the intake cam position sensor and after that it’s having boost problems idles fine vacuum holds where it should but as soon as you take it out it won’t boost above 5 psi when it used to be at 14 psi now I’m getting a p0016 and I’ve seen people say that it’s a timing issue does anyone have any idea what I could do before putting a lot of money and time to retime it