For all those who just love to quote "if you have to ask", to each his own, but what makes you right???
"Asking" was part of my research, and I never expected to get more than 10 based on buses that I drove. However, I still wanted to know for several reasons. An important one is if you routinely get 8 or 9 mpg, and suddenly get 2 or 3 mpg with no environmental changes, common sense... the same common sense for wanting to know, would tell you to start looking for problems before they get more expensive. Why is SilverLeaf surviving? Because many want to know what their engines are doing. So please, lighten up on those who are only trying to educate themselves.
/RANT MODE OFF/