Best way is to just replace the vac line for peace of mind. No sense in spending hours to find a small leak when you can just replace it in minutes for $cheap.
If youve got over 60-70k miles, you might as well just replace all vac lines. Might cost $10 for 10 ft of vac line. Some lines are harder to get to than others of couse, and if you do it all, figure a few hours to get it done.

 

good point. Can you recommend any place that sells replacment vacuum lines. I'd hate to go to the stealership as their prices are $$$

 

Id just go to the dealer if you cant find a euro shop that carries it locally. You may pay a little extra at the stealer but not much. Places like autozone etc didnt carry the sizes i needed. I wouldnt pay more than $15 at the stealer for 10ft of line.