hrm. consider a suggestion, you don't have to follow it, just consider it.

Before you rip out all the vacuum lines, and potentially introduce new problems, try finding the existing problem.

You know what I'm getting at? right now, you have one potential thing to track down, but if you change all of them, you're going to be second-guessing whether you did it properly.

I think the IACV might take a vacuum source.

Idle Air Control Valve, manual might also call it EACV.

-PHiZ