I use "
Fuelly.Com" to keep track of my road trips. I have over 17+K miles tracked on my GS Centennial Coupe (Manual) with a 23.7 MPG average with a best of 27MPG. My C5 Ragtop (3.15 gears) has 9+K tracked miles with an average of 24.5 and a best of 28.1. All are true numbers and not the DIC average.