| So here's what I've found out so far. At idle my intake manifold has a vacuum of around 20 to 21 ' Hg. Notice that I'm using an old gauge which seems to be biased about 1" Hg. The needle seems to be steady, but if I tap the gauge on the engine I can get it to resonate. Now I'm wondering whether this is an instrument error or whether the engine is actually vacillating like this. Hmmmm. Steady State Vacuum Gauge and Un-steady VIDEO One thing's for sure, opening the oil filler cap has absolutely no effect on vacuum. PCV Valve test failed VIDEO
The fact that my vacuum is higher than yours seems to rule out any major vacuum leaks, but is the 1" Hg increased vacuum on my engine indicating that something outside a vacuum leak being wrong? Is the fact that I can get the vacuum gauge to vacillate significant and indicating something's wrong? Should I buy a brand-new vacuum gauge to confirm what the 15+ year-old one is showing? Recognizing that opening the oil filler has absolutely no effect on vacuum should I be replacing the PCV valves and associated hoses? But do we reasonably believed that this is what's causing my engine to run rough, and run rich?
I haven't yet checked the voltage high and lows on the brand-new RHS OEM O2 sensor or on the old existing LHS O2 sensor. Any additional help would be greatly appreciated. 
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