ASE A8 is on Engine Performance, but is really more about emissions, ignition system, and diagnosing crank no-start conditions.

Healthy engine: 17-22 inHg

• Wobbling like crazy:
• 1 inHg low:
• Wobbling ~2-3 inHg back and forth:

Sources

https://www.youtube.com/watch?v=vl3WRIkbce0

https://www.youtube.com/watch?v=fpJB8nXawC8