I think I have a vacuum leak. My vacuum is normally about 14.9 - 16 ish when in park at idle. My engine starts fine but after a few seconds, when the idle drops to normal it starts slightly shaking or almost stuttering. In drive in traffic today I saw about 3.9 - 4.5 vacuum when at a stop light.
Also, I believe those figures are - since I'm obviously not building boost. My torque app reads them in + instead of - =P