I don't know about the timing yet, but I do know I have it slightly advanced to use midgrade fuel instead of regular. The power seems a little better that way.

About the duty cycle, heres what happens:

The car runs best at around 70-73%. If I turn the mixture adjustment to the right (rich) the reading goes up. It eventually maxes out at 90%, which I assume is the limit where lambda stops working. If I turn it left (lean) again and go towards 60%, it really starts chugging and sputtering. So what does this mean?

__________________
1985 380SE Blue/Blue - 230,000 miles
2012 Subaru Forester 5-speed
2005 Toyota Sienna
2004 Chrysler Sebring convertible
1999 Toyota Tacoma