I have a 12 inHg reading at idle- I think 17-22 inHg are spec.
I just did some testing on the car.
I took off the little 3 millimeter hose right underneath the 12 mm where it ends in the valve cover right above the oil filter (I don't know what these hoses all do there- probably inhaling vapors coming from the crankcase and burning it).
Funny, but when I took the 3mm hose off the fitting and tested vacuum on there I had straight 20inHg. When I put the hose back on the valve cover it was back to 12 inHg.
The leak is coming from the valve cover. I have no oil leaks at the valve cover. Any ideas?
Can this also be a reason for bad mileage- 17mpg?

Martin