Ethanol is hard on older cars mostly because of the water/corrosion issue. This is what I used to counter it.
Been testing Oil
I was very skeptical at first, but it works well and for several years has caused me no ill side effects. Just better mpg, and smoother idling.
I use supertech marine 2-cycle oil from walmart. Comes in gallons and I put it into clear squeeze bottles, with oz marks on the side. one gallon is good for 50 or so fill-ups and 1 oz per 5 gallon mixture.