If the 2.2 has a 2 barrel carb like the 2.6 Mr. Squishy the second barrel only opens up when pushed right down, that can explain some of the extra power feel, not to mention with only a 3 speed trans. that shifts up to keep the revs low for fuel efficience. As far as milage, no idea as I have not been out for a long road trip for years, mainly around town and short country cruises and have never kept track of it. I just sit back and enjoy
Martin