I put a few more miles on the 960 with the vacuum gauge installed where my now defunct fuel gauge used to be.
This is how it looks
2 more things I have noticed over the last few days. With a cold engine at idle in park, vacuum is 17" hg. When the engine warms up, idle vacuum rises to 19-20" in park. What does this mean? Im not sure if the knock sensors are the cause but i'm going to replace them anyway.
When I shift into D, vacuum drops by 1" in both situations.

This is the part that bothers me. At idle needle vibrates very fast + - 1". It vibrates so much that you can actually hear a buzzing sound from the gauge. This goes away as soon as I touch the gas. Everything I've read so far says this is supposed to indicate leaking valve stem seals and should be acompanied by oil consumption and smoke in the exhaust. But this engine consumes zero oil over 5000 miles and there is no smoke. It passed smog with flying colors a few months ago. Im starting to suspect leaking intake gasket or maybe one of the 6 hose connectors on the intake runners. What do you think?
Justin