A few things to consider.
- As noted, your car is still breaking in. Give it a couple thousand miles.
- The weather has cooled down. This means that it is now taking your car longer to warm up, during which time it is dumping fuel in open loop mode. EPA testing is not done at these kinds of temperatures, and the car warms up more quickly. This takes a significant hit on your fuel economy.
- Your tire pressure may have dropped since you purchased the car due to a drop in outside temperatures. Even a few PSI will make the difference. Check those and make sure it's correct.
- EPA testing is done with 100% pure (ethanol-free) 91 octane fuel. What are you using? We have proven here that there is considerable fuel economy to be gained by using high octane fuel (91/93). Furthermore, you are now on a winter blend fuel, which contains less total energy than a summer blend fuel, and chances are you are using some percentage of ethanol.
All of these factors combined will result in a fuel economy lower than what you may have expected or read about. See my article on getting better fuel economy if you want a few tips on improving this, but don't expect to be hitting over 30mpg if you're sitting at traffic lights most of the time. What's your average speed showing?
1. Yes, I only have 350 miles. I remember my Malibu started getting better MPG's when I hit over 1,000 miles.
2. I did notice the Cruze takes a while to warm up. The temperature gauge stays on cold for about 4-5 minutes. With the Malibu, the temperature gauge started to rise within a minute. Once the Cruze warms up, the heat is great. It was really cold the other day and I didn't even have to set the thermostat all the way up. It got too warm. With the Malibu, I had to keep the thermostat all the way up to get good heat.
3. The tire pressure is where is should be. They're showing about 35-37 PSI in each tire, so that's plenty of pressure.
4. I'm actually using regular gas. Premium is so much more expensive where I live - about 40 cents per gallon. I know that turbos get better fuel economy with Premium, but the car runs fine on regular.
I'm actually seeing better MPG's already. Today, I got up to 30 MPG with mixed city and highway driving. Previously, I was getting 28-29, so it's already improving.
I'm going to reset the 2nd set of fuel data when I get on the highway. I'd like to see what I get with pure highway driving. If I'm getting 30 MPG with mixed driving, I'll probably get in the high 30's with pure highway driving.