I am wondering if anyone is having this problem. Whenever I fill up my Dodge Caravan, and my wife's 2004 Honda Civic, the Check engine light comes on after about 25 miles, It stays on for the next 100 or so miles then just goes off.
I have heard the the gasoline in being reformulated with 15% Ethanol instead of the 10% we have been using for years now.
Can that be effecting the Emissions systems? I read both with a scanner and there are no trouble codes displayed.
I am stumped.
I am not using one of those cheap scanners. My son has a scanner that uses specific 'cards" for the application and reads EVERYTHING.

Any thoughts on this?
Thanks