Well, first off, I'd advise on breaking it in without paying attention to gas mileage yet. The two are at odds with each other when this car is new. The engine, trans and driveline are "tight" and need to be run through the entire operating range as much as possible without maintaining a constant, gas-mileage-inducing speed - the owner's manual advises NOT holding a constant speed, but instead varying your speed at all times for the first 2,000 miles. That is really how you break everything in - and it's fun at first but can get tiresome always slowly accellerating or decelerating, but it is WORTH it for anyone who has done this and then owned a well-running car for many, many many miles. Gas mileage will suffer - but it will suffer anyway if the car is new and tight also, so go for it...run it hard for short breaks after it's been rolling and warmed up for a spell even...moving some extra fuel through the manifold, injectors and heads is a GOOD thing!
Second - I didn't notice if your car is a manual or automatic. My GT with manual trans has, so far, recorded an extended steady "high" MPG of 26.9 on a trip down a long, straight and relatively slow country highway where we were maintaining about 60 MPH or so behind other steady-speed traffic.
Most importantly, to get the most accurate indication in my opinion, be sure to reset the "Average MPG" on the computer at every fill-up, so you won't be looking at the collective average measured since the car was born. I also reset the trip odometer and average speed before pulling away from the pump.
Second - I didn't notice if your car is a manual or automatic. My GT with manual trans has, so far, recorded an extended steady "high" MPG of 26.9 on a trip down a long, straight and relatively slow country highway where we were maintaining about 60 MPH or so behind other steady-speed traffic.
Most importantly, to get the most accurate indication in my opinion, be sure to reset the "Average MPG" on the computer at every fill-up, so you won't be looking at the collective average measured since the car was born. I also reset the trip odometer and average speed before pulling away from the pump.