BTW something is wrong if you are only getting 14 mpg in your Sierra. We have two and they get well over 18.
I live in the mountains and have a 4 mile dirt road to get home. It is 4x4 which knocks some millage off. Those clown cars could not get me home year round.
EPA killed the VW diesel because they said it polluted. I have smoke form the National Park forest fire they will not put out and they say I pollute?