Hi I have a 2012 Chevy Cruze 1.8L with 94k miles and I notice at about 80k that my gas milage started taking a hit. I used to get about 24MPG in the city on 91 Shell but now I only get 21.5 or 20.. I've had my Oil changed 2k miles ago and have always put synthetic in, and always pump 91 shell 80% of the time. My Oil filter currently has 2k miles on it but is going to be changed to a K&N in a few days and my Air filter might as well since I have about 15k miles on it. I am a very aggressive driver but I always have been and recently my fiancé who drives like a 90 year old saint can barely break 24 MPG when she used to be able to get 26+MPG out of her driving. Anyone have any suggestions as to what should be replaced to solve this? Chevy already reset the ECU to clear the transmission's memory.