[boxfix]

I had the same problem and it turned out to be a huge vacuum leak.

the Vacuum reservoir failed on my 2003. I also had the check valve that inserts in the manifold to source the vacuum fall out.

So I had very little vacuum to run the SAI system and the other items actuated by this vacuum system.

Get a vacuum gauge. Insert it into the system with a "T" connector and see if you are getting 15 to 20 " Hg reading. I was getting close to nothing in vacuum.


Next test the reservoir. Hook a hand vacuum pump with gauge directly to the reservoir. See if it will hold vacuum. If not replace the reservoir......they cost about $20.00. The reservoir is made in 2 pieces and glues together. It is a common failure that it becomes unglued. Mine would hold no vacuum. You do not have to un-mount it to test it. Use long needle nose pliers to remove the rubber fitting and attach a hose from the tester.

Look at all the vacuum lines. The lines are plastic with rubber connection pieces. the rubber ages and cracks. I have replaced as much of the Porsche vacuum lines as I can reach with 4mm high temperature silicon hose.

There are several good vacuum posts on this site.

Keep us posted and ask lots of questions. Particlewave knows his stuff!! He helped me a LOT!!