Checked vacuum as per another respondent regarding a possible partially plugged CAT. Read 17 IN/HG. In that area past 15 IN/HG, the scale says that may be possible late ignition timing problem. No timing light.
Now I got a timing light. Looked in the ignition section of the Bentley manual. Found that the timing should be lining up the timing mark on the flywheel with the reference mark on the bell housing. There's open area near and behind the distributor for that. I cannot find the timing mark on the flywheel while running the timing light.
While attempting to locate the timing mark, I moved the distributor's housing counter-clockwise. This increased the idle speed somewhat. Clockwise, the opposite occurred. Left the distributor housing fully counter-clockwise position (vacuum advance housing hits engine). Its obviously too advanced now as the engine pings when going up steep hills (many here). I know I need to back it off some. Oddly, there's not any real indicaton of pinging when flooring gas pedal while in high gear on level road. Any hints on finding the timing mark on the flywheel?
Timing light is a direct connect version, no induction connection. Car details -
88 VW Fox wagon 1.8L CIS-E, all stock components 350K plus miles