Welcome to the forum!
From when I removed the intake manifold off my 2.8tu, I know how bad the vacuum hoses can be
Intake pipes
My post MAF intake pipe has a HUGE hole right in the crease where it concertinas, so that was definitely not helping my engine.
Vacuum pipes
I think this is 2.8 only but.... There are two bits coming off the vacuum unit, which is accessible without taking the intake off, both of those were awful, more holes than pipe. One goes up to the fusebox (as it travels with the with the main loom to the exhaust valve in the backbox) and the other goes up to behind the intake manifold and meets at a joiner in line with where the intake meets the head. Then from there it travels by hard vacuum line around the engine to near the secondary air pump and switches to rubber line (mine was also very perished) before going into the thing with the silver cap (not quite sure what it does but it is near the front offside of the engine). There are also 1-2 vacuum lines relating to the CCV which I changed as they were crap.
I have heard the smoke test works well
It would be helpful for you to add what engine is in your z and location to your profile so people can give specific advice, and saving you retyping it each time. This can be done my clicking on your username near the top right corner and going to account details.
This is a link to a thread to help with parts buying:
Smudgemanuk submitted a new resource: Part Buying Guide For Newbies - Part Buying Guide For Newbies Hi all, welcome. I thought I would make a part buying guide for people new to the forum, as I found it quite daunting for the first few weeks of owning my z Step 1 - Finding part numbers...
zroadster.org
Hope this all helps a bit!
Chris.