for #2, need to goose the throttle to see the dist move, not just up idle - it changes w/ strong change in vacuum, and returns as vacuum normalizes - you could try setting the timing w/ a vacuum gauge, might be more accurate for mileage
that's suprisingly low, but you may not be able to get anymore than 12-13mpg, and a 228 may just be a gas hog - never checked the one I had cuz I only used about 2 tanks of gas a year anyway!
the gear change could help, tho you might eat the gas gettin up speed instead - the way you drive is a lot of what mileage you get - shift to keep rpm's in the low/medium range, don't mash the pedal - and of course you need to make sure your mileage is true - speedo and odometer may not be accurate
Bill
