heavy haul truck, that don't like heavy hauls!

[un_yun]

I have thought about the winter fuel too. I know mileage suffers in the cold months, I really don't stress about mpg's doing what we do. But it always helps to kinda know where it should be. That way you can sorta tell if something is off. And this is my first ISX and I bought it used, so I didn't really know what to expect. I did expect better than a v8 mack though.