Long story short- One day my car over heated and I unscrewed the radiator cap to have loads of hot water blow all over my engine (Idiot, I know) :bawling:. So i get it up and running and after that my mpg indicator started acting wierd. I can give it gas and the mpg gauge wont react until I'm at a certain RPM. What caused this? Any ideas? What indicates our mpg gauge to move?