[Cruze2.0Diesel]

I had a customer who was dealing with poor fuel economy, needed a locking gas cap. You could have the dealer check the fuel trims but really I agree the short trips are murder on MPG's, highway or not. Take it out on a long trip and see what she gets.

 

[Cruze2.0Diesel]

Ethanol is now are method of improving the anti-knock quality although it has less energy density. The knock sensor will retard timing which has a negative effect on engine performance if the fuel detonates. I agree with the previous two posters, you need to get out and warm that baby up and get her broke in, let it burn off some of those deposits and any condensation in the crankcase.