[boxfix]

I had the same SAI code problems.

I found that the check valve on my 2003 had fallen out of the rubber manifold. I fixed this with a brass barged fitting that I plugged into the rubber manifold and they used a piece of high temp silicon tubing to connect it to check valve.

I also found that the vacuum reservoir was leaking. This is a common problem. I tested the installed reservoir with a vacuum pump and gauge. It would not hold vacuum. A new reservoir is a little more than $20. I installed a new one and hooked up a vacuum gauge to the system and pulled 16 Hg to 19 Hg. Which is good and where it should be.

With these fixes my vacuum problems were cured.