Also when I researched this a few years ago most modern gasoline engines/fuel systems changed from using Butyl or Nitrile O-rings and seals to Dupont's,"Viton" which is impervious to the effects of Ethanol.I don't know what year but I suspect late 1980s/Early 1990s.
So if any older vehicles do have O-rings and Seal problems replacing with Viton versions should hopefully help
