All hoses needing replacement for surging idle?

[cutchemist42]

85 318i with the surging idle problem.

I've read in the Bentley and many other posters that the best place to start diagnosing the problem is by replacing the hoses and ensuring no vacuum problems.

I've read the Pelicanparts DIY and looked on realoem.com trying to determine all the hoses needed but having difficulty knowing what exactly to order.

Anyone familiar with part numbers, amount of hose needed, and the right size of hoses needed?

Thanks!