Interesting that Jon in AZ would mention a 2019 Ford Explorer. I tow our 2005 17' Casita
Spirit Deluxe with a 2009 Chevy Trailblazer with a 4.2L engine. I had issues with the check engine light
coming on when I was using regular unleaded fuel. I read an article, put out by Ford, that recommended that when towing with a Ford Explorer, use premium unleaded. I switched to mid-grade unleaded and the check engine light
doesn't come on as often.
The service code that comes up is a lean engine code. The light
usually comes on right after we fill up and get back on an interstate. Usually getting back on the highway, I have my foot to the floor and that's probably why it comes up with a lean code.
Any other time, when NOT towing, the light does not come on. Hope this opens some eyes and helps others realize the strain we are putting on our tow vehicles.