It's common on any year Z. It's more common on 8,9,10+ year old car, no matter what the make or model.
Old vacuum hoses are bound to crack and leak. Time to roll up the sleeves and dig, get dirty, and try and locate that CLB leak.

 

Vacuum is created by air & fuel being pulled into the combustion chamber by the pistons during the intake stroke on a 4 stroke motor. Easy way to remember it. suck (intake), squeeze (compression), pop (combustion), puh (exhaust). Many of the components in the engine are controlled by vacuum, so when you have a vacuum leak, your car will not run as well.

 

So, on an N/A car, a vacuum leak can come from just about anywhere between the air intake and the combustion chamber. On turbo's, the negative area on the boost gauge is vacuum. When the turbos are not generating boost, a vacuum leak can be present anywhere between the intake and the combustion chamber. When the turbos are generating boost, you can have a vacuum leak anywhere between the intake and the turbo. If you have a leak after the turbos, then you'd be leaking boost pressure. Hope this answers your question.

 

what exact hoses should we check for a vaccum leak on N/A's
im almost 100% psoitive i have vaccum leak and im really wanting to fix this,

thanks for any feedback!

 

You should be looking for any of the many small diameter hoses around the engine. They'll usually branch off of the intake tubes, egr valve, and generally are located to the sides and behind the upper intake plenum.
Good luck.

 

It's like finding a needle in a haystack. Happy hunting.

 

Those hoses are usually about 3/16 to 5/16 size hoses aren't they. I had trouble with the 240sx cruise control it was a split line where it went over the nipple to the vac pod. Check everwhere there is a connection, for bad ends seems like thats the first place that goes, oil and heat really wreek havoc on older vac lines. Was looking at an 88 turbo 300 the other day, never seen so many lines in my life.

 

http://www.300zx.co.uk/cgi-bin/manua...ault&total=190

here in the online manual, I came across some of the diagrahms for the vacuum lines.