Dave Plowman (News) wrote:
Do you know what the vacuum reading should be?

21" with the needle steady, not wobbling, is considered good. It had
been so long since I had last used one that I had to get on the
Internet to look up how to go about using one.

How to Use and Interpret a Vacuum Gauge
http://www.secondchancegarage.com/public/186.cfm

sound like the carb is faulty. Presumably being a late
type it has electronically controlled mixture and idle speed?

No. The Oldsmobile 5L/307 cid V8 is the last of the carbureted engines.
The carburetor (US spelling) has a throttle position sensor, but
everything about the carburetor's operation is mechanical, not
electronic, unless there's something I'm overlooking.

Thanks.