[dcb]

Also, you might try going into the code and changing both references to delay(2) to delay(12) and reverify/upload.

Also maybe try changing:
lcd.print("OpenGauge ");
to
lcd.print("0000000000000000");

just to see what happens.

It might be nothing too, just some strange result of nothing being connected to the board. To test that, modify Trip::mpg so it returns a 0.0 first thing:
double Trip::mpg(){
return 0.0; //add this line for testing display