PS I changed the fuel filter twice on this most recent trip of 1700 miles.
Also, I am advised that more than 10% ethanol is not good for older engines, so additives containing ethanol should be avoided.
Good, so now we know it is not the fuel fliter.
You are still getting bad advice.
E-40 will help, not hurt older engines, as it will clean the gunk out of them.
Even E-85 will not cause damage in older cars like my 92 Chrysler. It will slightly degrade performance in engines not tuned and set up for it, in that it takes a scond or two longer to start your vehicle and your cruise control will not hold your speed on hills very well, but it will not damage engines.
Here is a news flash; Engines run on straight gasoline sometimes fail too. Ethanol is just a handy scapegoat to blame for any engine failure.