Just to summarize and allay any possible misconceptions or confusion for readers of this thread, the basic mechanical mixture adjustment will not make any difference in warm engine operating characteristics, including fuel economy, as long as all KE system components are in good working order, including average duty cycle readings at idle and 2500 that are within 20-25 percent of each other.

The basic mixture should only be adjusted if there is a significant difference in average duty cycle at idle and 2500 RPM.

If adjustment is deemed as necessary, adjust the idle duty cycle to a little under 50 percent at idle. This will provide a slightly rich basic mixture, which should provide good starting and warm up driving characteristics.

With the idle duty cycle a little under 50 percent, the 2500 RPM duty cycle will probably be a bit over 50 percent.

Duke

P.S. I pulled my window sticker out of the file and found that the EPA ratings are 18/26. I corrected my previous post. Recall that my car is a five-speed and the autos probably have lower highway mileage. You can look at the EPA web site for the auto trans EPA mileage numbers. These cars were not economy champs, but technology has steadily progressed to a point were a modern sedan that is 500 pounds heavier and has at 50 percent more power has higher EPA numbers.